CA1211527A - Electric utility communication system with field installation terminal and load management terminal with remotely assignable unique address - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A powerline carrier communications system in-cludes a plurality of types of load management terminals, each of which has a unique address, and a combination field configuration and test terminal which can be plugged into the load management terminals. The combination terminal is coupled to the powerline through the connection to the load management terminal and generates a separate set of test commands for each type of load management terminal, which are transmitted over the powerline for execution by the connected load management terminal. Some types of load management terminals include an INITIALIZA-TION ENABLE line which, when activated by the connected combination terminal, commands the load management terminal to accept and store an address value received over the powerline as its new unique address.

Description

1 50,362 ELECTRIC UTILITY COMMUNICATION SYSTEM
WITH FIELD INSTALLATION TUNNEL AND LOAD
MANAGEMENT TERMINAL WITH REMOTELY
ASSIGNABLE UNIQUE ADDRESS

BACKGROUND OF THE INVENTION
The invention relates generally to an electric utility communication system for remotely reading meters controlling customer loads, and operating distribution equipment and, more particularly, to a system including a plurality of types of load management terminals, some with remotely programmable unique addresses, and a field install lotion terminal for testing and loading addresses into the load management terminals.
Electric utility companies are increasingly turning to communication systems in their continuing efforts to increase the reliability and control the cost of supplying electrical energy to their many residential and industrial customers. Such systems are used to remote--lye read customers meters from a central location and to remotely control distribution equipment, as well as to effect remote load shedding during periods of peak energy usage.
In order to exclusively address a single customer location out of the multitude of such locations an electric utility system, a communications terminal must be provided which responds to a unique address. Such a terminal is described and claimed in US. Patent 4,130,874 issued December 19, 1978 to Stephen M. Pet and assigned to 50,3~2 the assignee of this invention The terminal described in this patent is an interactive Tao 102d management terminal which can efficiently perform a variety of meter reading and load control functions. However, the unique address is physically Programmed into the terminal with wire jumpers or switches. It can be a time consuming process to open the load control terminal, select the proper settings, and reseal the terminal. The process is also prone to human programming errors. Another problem is that once the wire jumpers are installed, it it Defoe cult to change the address.
Load management terminals such as described in the aforementioned patent are quite complex and can execute multiple load control and data acquisition lung-lions as well as provide a large amount of status and error data. The manual testing of such devices thus becomes increasingly costly and complex, and cay require large amounts of a skilled operator's time. Furthermore, load management terminals, when installed in the field, are electrically connected to the purloin and caution must be exercised in the testing.
It would therefore be desirable to provide a communication system which includes a load management terminal responsive to a unique address which can be more simply and reliably programmed. Furthermore, it is desire able to provide means for efficiently testing and assign-in addresses to such terminals in the field.
SUMMARY OF THE INVENTION
In accordance with the present invention, elect trig utility communications apparatus is provided which includes a load management terminal connected to the power line and obtaining operating power therefrom. The terminal includes a receiver coupled to the purloin for receiving a carrier signal imposed thereon and means connected to the receiver for controlling loads in response to the carrier signals. The apparatus further includes a test terminal removably connected to the load management ton-3 50,36~
final and deriving operating power through the load manage-mint terminal. The test terminal comprises a test trays-miller connected to the purloin for imposing carrier signals on the purloin, and means connected to the test transmitter for generating test commands for the load management terminal. The test terminal further includes means for modulating these commands onto the carrier signals generated by the test transmitter, whereby the commands are transmitted over the purloin and received by the load management terminal receiver to cause actuation of the load control apparatus and test the operation thereof.
A communication system is also provided wherein a load management terminal is connected to the purloin or other communications medium and includes a memory device for storing an address value to which the terminal will uniquely respond. The address value can be received by the terminal over the communications medium and stored in the memory device to be accepted as the assigned address of the load management terminal whenever an initialization enable line is actuated. A test terminal is also provided which is removably connected to the load management ton final and which can actuate the initialization enable line to permit the load management terminal to accept a value I received over the communications medium as the uniquely assigned address for that load management terminal.
Furthermore, the test terminal can include means for receiving an operator entered address value and for trays-milting this address value over the communications medium concurrently with the activation of the initialization enable line, whereby the oparator-entered address value is accepted as the uniquely assigned address of that portico far load management terminal.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the present invention can be obtained by considering the following detailed description with refererlce to the accompanying drawings, in which:

50,3~2 Figure 1 it a block diagram of a purloin communication system including a plurality of types of load management terminals, and a field configuration terminal for testing and assigning addresses to the load management terminals;
Figure 2 is a perspective vowel of the field configuration terminal shown in Figure ]
Figure 3 is a block diagram of the interactive two way load management terminal shown in Figure l;
Figure 4 is a block diagram of a distribution control terminal for remotely controlling distribution equipment from a central location, as shown in Figure 1;
Figure 5 is a block diagram of the field con fig-unction terminal shown in Figures 1 and 4; and Figures PA, 6B, 6C, and ED are flow charts describing the operation of the field configuration ton-finals shown in Figures 1, 3, and 5.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Description of Communication System Referring now to the drawings in which identical reference characters refer to corresponding elements, Fig.
1 shows a block diagram illustrating a purloin commune-cation system 10 of an electric utility for communicating between a central station 12 and each of the utilities' customers. Typical customer locations are designed aye, 14h, 14c, 14d, aye, 15b, 15c~ 15d, eye, aye, 16b, 16c, 16d, aye, 17b, 17c, aye, 18b, and 18c. An electric utility distribution equipment location 20 is also shown.
Such a location could include a variety of equipment, however, in Fig. 1, a capacitor bank aye is shown, con-trolled by an operating switch 20b.
The customer locations Audi, Lowe, aye-16d, aye 17d, and awoke are representative of subgroups or sub geographical areas containing hundreds or a few thousands of customer locations being supplied electric power from the secondary purloin conductors S of a purloin distribution system 19. The secondary conduct Jo S 50,362 tars S are connected to large numbers of distribution transformers TRY typically required to serve the previously mentioned numbers of` customer locations. The high voltage side of the distribution transformers To are connected to 5 a primary purloin conductor P served ho substation 21 which is representative of one or more of such substations required to serve a large geographic area of customers, including all the customer locations shown in Fig. 1.
Each of the customer locations shown in fig. 1 lo includes one of two types of load management terminals (LOT) 24 or aye. The terminals 24 are interactive two-way communication terminals, indicated by To which provide two-way communication between the substation 21 and the various customer locations. The terminals aye are one-way 15 load management terminals, indicated by T, which provide load control functions in response to one-way communication fryer the substation 21 to the customer locations.
A distribution control terminal (DOT) 29 is provided at the equipment location 20, and is similar in 20 function to the interactive Lots 24 and the one way Lots aye. The functions of each of the terminals 24, aye, and 29 will be described in greater detail.
Each of the customer locations Audi, Audi, Audi, and Audi may also include metering apparatus . 25 having a pulse initiator or encoding register for measuring and encoding the consumption of electrical energy supplied to customer loads 28. Communications carrier signals are transmitted between the Lots 24 and the substation 21 through the distribution line conductors 30 P and S which also have associated two-way repeaters 30 forming the communication system 10.
The one-way Lots aye also provide communications capability to their corresponding customer locations.
Louvre, they do not have the capability of communicating 35 in a reverse direction from the customer location to the substation 21. Each of the Lots aye thus responds to load control commands transmitted from the substation 21 to 6 50,362 connect and disconnect portions of their associated loads 28.
The DOT 29 includes two-way communication keep ability similar to that of the interactive Lots 24. How-S ever, rather than connecting and disconIlecting portions of customer loads, the DOT 29 controls various types of distribution elopement belonging to the electric utility.
In the embodiment shown, the DOT 29 controls a switch 20b to connect and disconnect a capacitor bank aye to the primary side of the purloin distribution system lo. In addition, the DOT 29 includes the capability to receive ( analog input data from the electric utility equipment and transmit this information back to the substation 21. In the embodiment shown in Fig. l, a current transformer 20d is provided which provides current flow information to the DOT 29 for transmission back to the substation 21 and further communication to the central station 12.
One example of a communication system using the purloin as a communications medium is described and claimed in US. Patent No. 3,911,415 issued October 7, 1975 to Ian A. White and assigned to the assignee of this invention. However, the present invention is not limited to such purloin communication systems as described hereinbelow or in the aforementioned patent.
Referring once more to Fig. 1, carrier communique-lion signals are impressed on and received from the power line conductors P and S by transmitters and receivers (not shown) at the substation 21 and at each of the terminals 24, aye and 29. The two way repeaters 30 are coupled to the purloin conductors to amplify and retransmit the carrier communication signals as they are transmitted over the purloin conductors. An example of one repeater arrangement suitable for use in the communication system 10 is described and claimed in So Patent No. 3,942,170 issued March 2, 1976 to White and US. Patent No.
3,967,264 issued June 29, 1976 to White et at., both Jo assigned to the assignee of this invention Ed hub ..~

The com~mication link 32 between the central station 12 and substation 21 may be formed by a conventional telephone line. As has been described in the aforementioned patents, the communication carrier signals are modulated with 5 binary coded messages containing command, interrogation, and status data to be communicated between the central station 12 and the locations of the terminals 24, aye and 29. These terminals are provided with a plurality of address formats and associated circuitry for response -to the addresses as described in detail hereinafter.
Also shown in Fig. 1 are a plurality of field configuration terminals (FIT) 26. The Fits 26 can be removably connected to the terminals 24, aye, and 29 to perform a variety of testing functions and to assign unique addresses to the terminals 24 and 29 in a manner to be described hereinbelow. Each of the terminals 24, aye and 29 is capable of receiving and being responsive to selective ones of a lmique address (US), a selected block address (SPA), or a universal block address (USA). The US
identifies each discrete terminal so that each of the locations Audi, aye, Audi, Audi, awoke, and 20 shown in Fig. 1 would have a separate and discrete binary coded unique address.
The SPA is the same for terminals at all of the locations of a selected geographic area. Accordingly, the terminals at locations Audi would have a common SPA and the terminals at locations aye would have a different common SPA. The terminals at locations Audi, Audi, awoke, and 20 have four additional and different SPA
addresses. The USA is common to all of the terminals of the locations of a large geographic area. Accordingly, all of the terminals 24, aye, and 29 shown in Fix. 1 have the same USA.
description of LOT 24 In order to understand the construction of the interactive LOT 24 in greater detail, reference may be had X

8 50,362 to Fig. 2. Ire LOT 24 is similar in function to the LOT
described and claimed in the aforementioned U. S. Patent No. 4,130,874. The format of the message words transmitted and received by the LOT 24 it identical two that described in the aforementioned U. S. Patent 4,130,874.
The major difference in function between the LOT
24 and the LOT described in US. Patent No. 4,130,874 is that the unique address US of the LOT of the patent is physically coded whereinto by wire jumper connections to its circuitry. 'the LOT 24 described he-rein as part of the present invention has the capability to accept as its unique address an address value down-loaded from the central station 12 by of a message transmitted over the communications medium. By energization of an INITXALIZA-TON ENABLE line, to be described hereinbelow, the LOT 24 is commanded to accept a unique address so transmitted.
Accordingly, unique addresses can be assigned to the Lots 24 from the central station 12 of Fig. 1 in conjunction with the energization of the INITIALIZATION ENABLE line by an FIT 26. However, in most cases the unique address will be assigned to the LOT 24 by an address value entered by an operator in the field into an FIT 26.
Structurally, the LOT 24 is quite different from that disclosed in the aforementioned US. Patent 4,130,874 in that much of the circuitry has been rearranged, and the LOT functions consolidated and implemented through the use of a microprocessor. A block diagram of the LOT 24 is shown in detail in Fig. 3. The microprocessor 27 shown in Fig. 3 is a type SCOT obtainable in commercial quanta-ties from the Motorola Corporation. This microprocessor is similar to the widely-known Sirius of microproces-sons and uses the 6800-series instruction set. However, this specific device, originally developed for apply-cations in the automotive industry, can successfully 9 50,362 operate o'er a much wider temperature range than the standard Sirius microprocessor. In the disclosed embodiment, the microprocessor 27 it not an integrated microcomputer but rather an arithmetic logic unit utilize in a plurality of external circuit devices to perform the desired functions. However, as is readily apparent to one skilled ion the art, other circuit configurations are equally suitable to perform the f-unctions of the present invention.
A clock circuit 30 is provided to generate a stable series of 1 mHz clock pulses to the microprocessor 28. Other inputs to the microprocessor 27 include a reset line activated in response to conditions described herein-below and an interrupt line connected to a timer 48 to aid in performing demodulation functions on carrier signals received from the secondary purloin S. The microproces-son 28 is connected to an address I* bus 34 and to a data bus 36.
As is well known to those skilled in the art, the instruction set of the 6800-series of microprocessors does not include input and output instructions as such.
Rather, such input and output functions are performed using commands similar to memory reads and writes. The associated input and output devices are mapped into the memory of the microprocessor 27 such that when an output is desired to a specific outboard device, a write command is directed to a specified memory address associated with that device. Accordingly, a plurality of input and output devices are connected to the microprocessor 27 through the address bus 34 and data bus 36. The input and output devices associated with the microprocessor 27 include a random access memory (RAM) 40, a non volatile RAM 42, a read only memory (ROM) 44, a buffer 46, the timer 48, and a programmable interface adapter (PI) 50 which functions as an input/output port for the microprocessor 27. In order to properly access each of these devices, an address decode device 38 is provided.

50,362 When the microprocessor 27 desires to access one of the associated devices 40-SO, the address associated with that device is placed on the address bus 34. I've address decode device 38 receives this address and deter-mines the associated device 40~50 which corresponds there-to. The address decode device 38 then energizes an appear-private ENABLE line aye, aye, aye, aye, aye, or aye to cause the proper device and only the proper device to either accept data from, or place data on, the data bus 36.
The RAM 40 is a type 6810 obtainable in emery-( coal quantities from the Motorola Corporation. This device is used to store the changing data quantities produced by the microprocessor 27 as it executes the functions of the LOT 24. It is to be understood -that more than one of such devices can, of course, be used, with appropriate memory mapping functions coordinated with the microprocessor 27.
The non-volatile RAM 42 is a type HM6561-9 obtainable in commercial quantities from the Harris Corpora anion. The data stored in this device will remain secure even though operating power to the device may be inter-rutted. This function is provided by a memory protect circuit 52 supplied by a battery 54 and activated by reset and power down inputs which are in turn activated at appropriate times by a power supply 70.
The operating program instructions for the microprocessor 27 are stored in the ROM 44. This device is a type IDEA electronically programmable read only memory available in commercial quantities from the Intel Corporation. It is to be understood that certain embody mints of the present invention may require more than one such IDEA device.
The buffer I is provided to accept data from a pulse initiator 56 of associated wither metering appear-anus 26. As is well known in the art, the pulse initiator 56 produces output pulses at a rate proportional to the I

11 50,362 consumption ox electrical energy on the circuit being metered. These pulses are stored in the buffer 46 and are delivered to the data bus 36 upon command of the micro-processor 28.
The timer 48 is a type 68~0 device obtainable in commercial quantities from the Motorola Corporation. This device periodically generates the interrupts necessary for the microprocessor to perform demodulation functions as described in US. Patent No. 4,311,06~ issued January Lo 1982 to John R. Bikini and assigned to the assignee of this invention. The timer also produces a train of pulses of a frequency of, for example 12.5 kHz to form the carrier signal utilized in transmitting messages from the LOT 24 over the purloin So The PI 50 is a type MC6821CP device obtainable in commercial quantities from the Motorola Corporation.
It functions as an input/output port for the microprocessor 28 and is connected to a variety of devices supplying input to or receiving output from the microprocessor 27.
A plurality of relays 58 are connected to the PI 50 to energize and reenergize associated loads 28 from the power line S. These relays are energized in response to commands generated by the microprocessor 27 which are in turn requested by signals received over the I purloin S
from the central station 12.
Also attached to the PI 50 is a buffer 60 whirl stores the position of up to six two-wire contact closures.
These closures would typically be used to monitor load control function, provide a tamper indication for either the meter or the terminal electronics, or monitor a service disconnect function. Upon command from the microprocessor 28, the PI 50 will request the buffer 60 to supply the state of the status contact closures to the PI 50. This information will then be placed by the PI onto the data bus for transmission to the microprocessor 27. The buffer 60 is a type LM3302 device obtainable in commercial quanta-ties from the National Semiconductor Corporation.
X

I 50,36~
The INITIALIZATION ENABLE input line is also connected through the PI 50 to the microprocessor 27.
When (and only when) this input line is activated by placing it at ground potential an address value received by the terminal 24 or I over the communications medium, such as the purloin S, will be stored by the micro processor 27 in the NV RAM 42 and will become the assigned UNIQUE address for that terminal.
Although the most common procedure for assigning a ICKY address to the LOT is for a connected Field Configuration terminal to ground the INITIALIZATION ENABLE
( line and transmit an operator-entered address value to the LOT, the central station 12 may assign the address value by a message transmitted therefrom, if the INITIALIZATION
ENABLE line of the LOT is grounded by a field worker.
An additional buffer 62 is connected to the PI
50 to supply input from a register shaft encoder 64 which is also part of the wither metering apparatus 26. The apparatus 26 may have a standard four-or five-dial output register which provides the meter reading to the customer.
The encoder 64 determines thy angular position of the shafts of this register and provides an electronic signal ! representative of the angular position of each shaft to the buffer 62. Upon command of the microprocessor 27, this information is transferred from the buffer 62 through the PI 50 onto the data bus 36 and thence to the micro-processor 28.
In order to provide the interactive communique-lions capability for the LOT 24, a receiver 66 and trays-miller 68 are provided. The receiver 66 is directly coupled to the AC purloin and senses the presence of carrier signals thereon. Binary coded message formats are carried by the phase-modulated carrier signal, which is band pass filtered by the receiver 66 and supplied to the PI 50. The 12.5 Ho signal is transferred by the PI 50 onto the data bus 36 and supplied to the microprocessor 27 which provides a demodulation function to extract the 13 50,362 binary coded messages therefrom. A more detailed descrip lion of the demodulation process is contained in US.
Patent No. 4,311,964.
it As can be seen in Fig. I, the transmitter 68 obtains an unmodulated carrier signal from the timer 48, and from the microprocessor 27 through the PI 50 obtains the binary message which is desired to be transmitted to the central station 12. The binary message is then phase modulated onto the carrier and amplified by the transmitter 68 before being coupled to the AC purloin S, over which it is propagated to the substation 21.
( A power supply 70 is connected to the AC power line S. The power supply 70 provides the necessary DC
operating voltages for the devices of the LOT 24, and also provides appropriate power down and reset signals to the memory protect circuit 52 to ensure that the contents of the non-volatile RAM 42 remain secure during periods in which the supply of power through the AC line S is inter-rutted. 3 As can be seen in Fig. I., the following conned lions are terminated at a socket 72: the output contacts of the relay 58, the INITIALIZATION ENABLE line 59, the status inputs 61, and the purloin S. The socket 72 thus - forms an effective means for connection of the LOT 24 to associated independent devices outside of the LOT.
Description of DOT 29 The distribution control terminal (DOT) 29 is very similar to the interactive LOT 24, with certain additional functions provided by components shown in Fig.
~.~ All other aspects of the DOT 29 are identical to that of the interactive LOT 24. As can be seen in Fig. 3, the inputs of a multiplexer 74 are connected to a plurality of transducers such as current transformer 20d. The output of the multiplexer 74 is connected to the input of an analog to-digital converter ARC 76. The multiplexer and ADO 76 may be type 4529B and 3711 devices, respective-lye both of which are available from the Matinal Semi con-14 50,362 doctor Corporation. The multiplexer 74 and ADO 76 are both connected to the PI 50. The ENABLE inputs aye and aye of both the multiplexer 74 and analc,g-to digital converter 76 are connected to the address decode device 38. Under command of the microprocessor 27, a select code corresponding to one of the transducers 20d is passed through the PI 50 to the multiplexer 74. The output of the selected transducer 20d is then supplied through the multiplexer 74 to the input of the ARC 76. The ADO 76 then initiates a conversation of the analog quantity produced by the transducer 20d and supplies the digital value of this analog quantity through the PI 50 to the data bus 36, where it is transmitted back to the microprocessor 27.
All other functions of the distribution control terminal I are identical to that of the interactive load management terminal 24.
Description of FIT Operation The FIT 26 is a portable microcomputer, used in support of the testing and installation of Lots 24 and aye and Ducts 290 As shown in Fig. 2 it is housed in a protect live case 80, which also provides storage space for the interconnecting cables.
A coiled, multi conductor cable supplied with the 26 is terminated in the plug 112 and is used to intercom-neat the FIT 26 directly Jo the LOT 24 or DOT 28. When a socket adapter it used, the FIT 26 can also be intercom-netted directly with socket-mounted Lots aye.
Power for the FIT is supplied through the con netted LOT or DOT. A protective toggle switch-breaker 81, located on the left side of the FIT 26 is used to control input power Although not visible in Figure 2, the switch-breaker 81 is illustrated schematically in Figure 5.
Except for the power switch-breaker 81, all operating controls are located on a front panel 82, which is recessed into the case 80. Ire tests performed by the FIT 26 are preprogrammed and must be performed in a sequence that is dictated by the resident software. Certain data, which it required by the program, is supplied by the 50~ 362 operator through a keyboard 84. Test mode selection, identified by terminal type, is made by a three position MODE switch 86.
The key pad 84 consists of a totally enclosed, pressure sensitive switch matrix that contains 16 keys.
The keys are divided into two function groups. One group of six keys, located along the outer border of the key pad, is the CONTROL group and includes:
TEST which initiates an FIT self test that causes all of the numeric displays on the display and if of the 13 LED indicators to light for approximately 3.5 seconds. The TROD PEAK and MID indicators are not illume noted.
COCK which clears data entries that are disk played on the numeric display panel. COCK
does not clear data that has bee entered via the ENTRY key. The test sequence number is not affected by the COCK Control. Data that has been entered by the ENTRY key can be cleared only by using the RET key.
RET which repeats the entire test transmission ; from the FIT to the terminal under test.
NEXT - which bypasses the test being conducted and proceeds to the next test in sequence, or, in the case of a program halt, causes the program to proceed to the next test.
ENTRY - which enters data that is visually disk played on the numeric display panel into the test program.
RET - which resets the FIT. it reinitializes the instrument and begins the test sequence again.
The other group contains 10 numeric keys (0-9) that are used to input numeric data into the digital display panel 88.

I , 16 50,362 The MODE switch 85 is a three position wrier switch that is used to interface the FCTr~and one of the three types of terminal equipment. These are specified as LMT~1 (corresponding to one-way LOT aye, LMT-2; Coors S pounding to interactive LOT 24); or DOT 29. An improper match of the terminal under test and the position of the MODE switch will be detected by the test program.
EXTERNAL STATUS 90 consist, of two toggle switches that are marked EXTERNAL STATUS 1 and 2. They lo control status flags within a connected DOT 29 to stab-fish the present state of the DOT relay contacts.
The Numeric Display is an eight digit display panel that visually indicates numeric entries made by key pad operation. Numbers called for in the test procedures are entered conventionally (reading front left to right) and progress serially across the display panel from right to left. Overflow is continuous at the left most digit.
Error signals are displayed if a test is unsuccessful.
TEST STATUS indicators aye are a pair of Lids that visually indicate that the unit under test has passed or failed any one of the tests in the sequence. A green GO LED indicates that the test was completed successfully.
A red NO-GO indicates failure. The GO LED stays lit for one second during the test sequence if the test is passed.
If the connected LOT fails the test, the red NO GO LED
remains lit until the test sequence is reset. While the NO-GO LED remains lit, an error signal appears in the display panel.
CONTACT TEST indicators 92b are paired red and green Levy labeled GO and NO-GO. Four such pairs are arranged vertically at the left-most side of the control panel. Each pair corresponds to a relay in the terminal under test. Contact status for latched relays is India acted by the uppermost pair.
TROD [PEAK, MID] 92c indicates the status, at the time the test is made, of the time~of~day rate schedule that it configured in a connected LOT 24. These indict-ions have no meaning in the LMT-l test mode for Lots aye.

17 50,362 install is a single red LED 92d that is lit only during the instillation procedure. It: verifies visually that the FIT is operating in the INNATELY mode and will transmit an operator-supplied unique address value to the S connected LOT, while activating the INITIALIZATION ENABLE
line, to cause that address value to become the assigned UNIQUE address for the connected LOT.
TEST NUMBER is a two-digit display panel 94 which displays the number of the test currently being conducted.
General Test Information ( After inserting the plug 112 into the socket 72 of tune terminal under test, -the power switch 81 is turned on and the TEST key pressed. The FIT control panel 82 is checked before a test routine is star-ted to make certain all indicators are functioning properly. All of the digits on the mlmeric display 88 and the TEST NUMBER
panels 94 will display us. All of the Lids, except TROD
(PEAK and MID), will be lighted. The numeric displays and the Lids will remain lighted for 3.5 seconds.
The numeric display panel is cleared by entering all "zero" digits or by using the COCK control key. The COCK key is preferred.
Tests numbered 2 through 5 require that data be input through the key pad. All tests numbered treater than 10 are performed in a predetermined sequence by the FIT without operator intervention.
To be considered valid, all numeric key pad entries must be accompanied by an appropriate single digit checksum which is the arit~netic total of all of the digits that are input. The right-most digit of a multi-digit checksum is to be used.
As an example, consider the input of UNIQUE
address 123456. The arithmetic total of the digits is 21 (1+2*3+4~5+6~ and represents the checksum. The rightmost digit of the checksum is 1. Thus, the UNIQUE address 1~3456 is input, followed by 1. The entire arithmetic entry is made before the ENTRY key is pressed.

18 50,362 Data displayed on the panel 88 is entered into the test program by the ENTRY key. So lorlg as the data remains displayed, it can be altered or deleted by using the COCK control key without affecting the test program.
If the data-checksum combination that has been entered is valid, the green GO LED in TEST STATUS will fight moment tartly and the TEST NUMBER at display 94 will increment.
Should the data-checksum combination be invalid, the red NO GO LED will remain lighted in TEST STATtJS aye and the lo data entry sequence will halt.
After data has been entered into the program, ( invalid entries can be cleared only by the RET control, which returns the test sequence to 01. This procedure clears all previously entered data and requires that all necessary data be reentered.
Test sequence 05 signals the end of the data entry procedure. The program halts at this step and remains halted unlit the NEXT key is pressed. Once into-axed by the NEXT key, the test sequence cannot be halted by the FIT operator. The sequence will continue to a satisfactory conclusion (GO) or will halt due to a test failure, displaying a NO-GO. In the event of a test failure, and thus a program halt, the sequence can be continued by pressing the NEXT key. At the conclusion of a test sequence, the sequence may be repeated without reentering the data by pressing the RET key.
Only one test can be performed on a one-way LOT
aye. It verifies the operation of timed relays. In-directly, this test also verifies the coding of the select ted Block Address since a miscoded address will consist gently produce a failed test NAGOYA) indication on all relay positions that were specified in the FIT Control Number.
There are three test sequences which own be performed on the interactive terminals 24 and 29: INSTALL
LOTION, TEST, and READ AND TEST. The INSTALLATION test sequence is used to initialize all interactive terminals 19 50,362 24 and 29 by downloading the terminal's UNIQUE address during the test procedure. The other two test sequences are used to operationally test interactive terminals after they have been initialized. The sequences are identical except for the mummer in which the UNIQUE address is checked. The TEST sequence requires that a UNIQUE address be entered into the FIT by the operator. This address is then compared with the address recovered from the inter-active terminal by an interruption command. I've test is useful for checking a suspected bad address.
The READ AND TEST sequence does not require the ! operator to input the UNIQUE address. I've UNIQUE address that is resident in the terminal is read from the terminal during the sequence and this address is used thereafter when required by the sequence. During the TEST and READ
and TEST sequences, the terminal's ability to respond to Selected Block Addressing is inhibited. This is reset to the pretest state by the last test procedure in either sequence.
Thea time required to perform each test in a sequence varies from test to test. During test intervals of longer than 3 seconds duration, both TEST STATUS Lids will blink once per second to indicate that the sequence is being performed.
Individual Tests Certain tests that are to be made prior to the various automatic sequences are common to all terminals and require that data be entered into the test program by the FIT operator, using the key pad. Other tests are specific to each terminal type and are conducted automatic gaily by the resident FIT test program after certain data are specified.
Test 01 is performed automatically when the EQUITY
is interconnected with the terminal to be tested and the FIT is turned ON. This test is also performed each time that the RET key is pressed.

50,~6~
The test determines whether the terminal under test and the MODE switch setting agree. If they agree, 02 appears in the TEST NUMBER window 94. If they are not in agreement, 01 appears, I` requires that the MODE switch be rotated to the appropriate terminal Lubell should now appear in the window. The ENTRY key does not have to be pressed.
TEST 02 requires that the numeric value repro-setting the terminal address be entered. Eight zeros will appear in the numeric display. The value is keyed (up to seven digits allowed) followed by the checksum digit, and the ENTRY key pressed. If a valid data-checksum Cowan Tony has been entered, three zeros will appear in the display window 88 and 03 will be displayed in the TEST
NIJMBER 94. If the numeric combination is not valid, the NAGOYA TEST STATUS LED aye will light.
TEST 03 requires the entry of a three digit code identifying the number and type of control relays con-twined in the terminal to be tested. This code is called the HOT Control Number and consists of the following:
First digit - C-4 The number of relays to be tested.
Second digit - O The LOT contains no latched relays.
( 1 Signifies that the condition of the latched relay is to be left in the same state as it was found before the test.

2 Indicates that the latch relay is to be left open after testing.

3 Indicates that the latched relay is to be left closed after testing.
Third digit I 7 Checksum.
ENTRY is pressed after keying the appropriate data. Two zeros appear in the numeric display 88 if a valid data-checksum combination is used; the test number also advances.

21 50,362 TEST 04 requires that the FIT operator select one of the three test types for LOT 24 or DOT 29. This information is not required for LOT aye and the tusk program skips this procedure.
Code 11 - INSTALLATION test. The FIT downloads a UNIQUE address to the terminal Code 33 TEST. The EQUITY tests for a match of the UNIQUE address entered into the FIT and the UNIQUE address residing in the terminal.
Code 77 - READ AND TEST. The FIT reads the UNIQUE
address residing in the terminal and disk plays it. The program halts after the reading is made.
If the four preceding steps have been acc:omp fished properly, the test number increments to 05 after the ENTRY key is pressed and the numeric data on the disk play panel is cleared. The panel remains blank.
Failure to perform any of the steps correctly will cause the data to remain on the numeric display 88 and the TEST NUMBER 04 will not increment.
TEST 05 is the beginning of the automatic test sequence and the data entry sequence is halted at this step. The appropriate test sequence will begin after the NEXT key is depressed.
Performance of the specific tests is type-dependent, with each sequence being programmed for the terminal type specified by the test MODE switch 86. The programmed sequence, which begins when the NEXT key is pressed, also depends upon the test type selected by the operator.
Satisfactory completion of each test is visually demonstrated by the TEST STATUS GO LED aye, which lights for one second, and by the advance of the number in the TEST NUMBER window 94 to the next test in the sequence.
This number remains lighted while the test is being per-formed.

22 50,362 Failure to pass a test is visually shown by the TEST STATUS NO GO LED aye, which remains lighted. The sequence halts; the current test number remains in the TEST NUMBER window 94; and an error code appears in the numeric display 88.
Pressing the NEXT key under these conditions causes the sequence to continue to the next programmed test.
Error Code Directory Winnie the FIT fails to perform a certain test properly, an error code is displayed what indicates the (; malfunction encountered during the test sequence. The following error codes may be displayed:
O No transmission from the FIT.
Thea following error codes do not apply to the one-way terminals aye.
1 No reception from an interactive terminal.
2 No second word in the message received by the FIT.
3 Bad BACH code on message received by the FIT.

4 Any data error in the received message, including the UNIQUE address.
Presence of a latched relay on the terminal does not agree with the FIT Control Number entered.
6 The terminal type-identifier encoded within the terminal memory does not agree with the type set by the MODE switch.
TAOIST PROCEDURE FOR ONE-WAY Lots aye 1. Place both EXTERNAL STATUS switches 90 of the FIT in the OFF position.
2. Insert the plug 112 into socket 72 on the terminal adapter. The FIT is now powered from the coy-netted terminal. Rotate the MODE switch 86 to the LOT 1 position before turning on the FIT. Turn on the FIT
power-breaker switch 81.

23 50,362 mu Check the FIT indicators on front panel 82 by pressing the TEST key.
4. Check -that 02 appears in the TEST NUMBER
window 94. Test 01 has tested the proper match of the MODE switch position and the terminal under test. If 01 appears in the window 94, the TEST STATUS LED aye will display NO GO, which indicates an FCT-terminal mismatch.
Rotate the MODE switch 86 to the appropriate terminal type and observe the number in the TEST BYWAY window 94 for an advance to 02.
S. Key in the LOT aye Selected Block Address SPA This number ranges from O to 59. Key in the checksum digit. Press the ENTRY KEY. If the SPA address checksum combination is valid, the TEST NUMBER will advance to 03 and three "zero" digits will light on the display panel 88. If the address-checksum combination is invalid, the TEST NUMBER will not advance. Press COCK to clear the invalid combination and try again.
6. Key in the number of relays in the terminal that are to be tested, followed by the appropriate check-sum (FIT control number). Press the ENTRY key. The test sequence will advance to 05, bypassing 04. The numeric display will blank.
7. Press the NEXT key. The test sequence starts by performing test 35, which tests timed relays.
8. The FIT 25 transmits the chosen SPA address and SHED LOAD Action Message over the purloin to the LOT
aye. Failure to transmit will result in Error Code O
being displayed in window 88. Approximately SO seconds will be required to complete the test.
9. Midway through the test the FIT will trays mix the SPA address and a RESTORE LOAD Action Message.
The display of Error Code O will signify an FIT failure (no transmission). Press RET to try the test again.
10. During the time interval that the FIT per-forms test 35, the TEST STATUS Lids aye will blink Somali tonsil once per second to indicate that the test is on-going.

24 50,362 11. Test 35 tests the high current relay of lot aye by transmitting a SHED LOAD command, followed by a RESTORE LOAD command. The relay contact closure is checked directly.
12. Successful completion of the test is India acted when TEST STATUS GO LED aye remains lit The A
level bottom of the group) CONTACT STACY GO LED 92h will also remain lit.
13. Failure to pass the test causes the TEST
STATUS NO-GO LET aye and the CONTACT STATUS (A level) NO-GO LED 92b to light simultaneously.
l 14. If an invalid FIT Control Number is entered, the TEST STATUS aye will display NO-GO at the completion of the test, but the CONTACT STATUS 92b will display GO
for the relays successfully tested.

The FIT can perform three test sequences on the These are:
INSTALLATION Code 11 TEST Code 33 READ and TEST Code 77 Test codes 33 and 77 are identical except for the identification of the unique address.
A description of each of the tests performed in the test sequences is contained in Table 1. These are listed by test number and the sequence in which they are performed. Error codes that may be displayed for each test are also listed.

I
US 50,362 POSSIBLE
TEST TEST ERROR
DESCRIPTION OF TEST NUMBER SEQUENCE CODES

5 download UNIQUE address 15 if O
Read and verify UNIQUE address 20 ]l/33/77 0,1,293,4 Read hardware configuration and verify whether an encoding register 164 or pulse initiator 56 is 25 ll/33/77 foe 10 used and whether a latched relay is present ( Read the status of the SPA address response 26 33/77 0,1,3 Inhibit SPA address response 27 33/77 0 15 reset all error flags, inhibit time sync flog, reset battery log 30 11 0 to zero Test timed relays 3511/33/77 0 Test latched relay, if present, and restore in accordance with 4011/33/77 FIT Control Number Read and display the reading of the encoding register 164 4511/33/77 0,1,3 or Read and display reading of the pulse initiator 56 4611/33/77 0~193 Restore SPA address response to the pretest stat 50 33/77 0 1. Insert the plug 112 into socket 72.
2. Rotate the MODE switch 86 to the LOT 2 position.
3. Turn on the FIT power-breaker switch.
4. Check the FIT indicators by pressing the 35 TEST key.
5. Check that 02 appears in the TEST NUMBER
window. Test 01 verifies a proper match of the MODE

26 50,362 switch position and the terminal under test. This is a hardware test. If 01 appears in the window, the TEST
STATUS LED aye will display NAGOYA, which indicates an FIT terminal mismatch. Rotate the MODE switch 86 to the appropriate terminal type and observe the TEST NUMBER
window 94 for an advance to 02.

6. Select the appropriate code for the test that is to be performed on the LOT 24 in accordance with the following schedule.
CODY TEST TYPE

If code 11 or 33 is to be chosen, key in the UNIQIJE address, then the checksum. Press the ENTRY key.
If the address-checksum combination is valid, the TEST
NUMBER will advance to 03 and three "zero" digits will appear on the display panel 88. If the address-checksum combination is invalid, the TEST NUMBER will not advance.
Press COCK to clear the invalid combination and try again.
The UNIQUE address is not keyed in if test sequence 77 is to be used. Reference is made to (10) below then to (7).

7. Key in the number of relays in the LMT-24 that are to be tested followed by the appropriate checksum (FIT Control Number). Press the ENTRY key. The test sequence will advance to 04.

8. If the INITIALIZATION sequence, code 11, has been chosen, the following sequence of tests will be performed: 15,20,25,30,35,46 - END.

9. If the TEST sequence, code 33, has been chosen, the following sequence of test will be performed:
20,25,26,27,35,46 -- WALT -- press NEXT --- 50, end of test sequence.
Sequence code 33 requires that the UNIQUE address=
checksum combination be input using the key pad. When the sequence starts, the FIT will check the UNIQUE address s I 50,~62 residing in the LOT 24 and compare it with the one disk played on the FIT panel 88. If the addresses agree, the sequence continues without interruption.
If -they do not agree, the sequence will halt and Error Code 1 will be displayed Use of toe RET key clears the FIT and reenter all of -the data required in steps 02 through 04.

10. If the REAR AND TEST sequence, code 77, has been chosen, the following sequence of tests is per-10 formed 20 HALT - press NEXT 25,26,27,35,46 - HALT
press NEXT - 50 - end of test sequence.
( Sequence code 77 does not ruler the input of a UNIQUE address. The FIT interrogates the LOT 24 and reads the UNIQUE address residing in the terminal. This data will remain displayed on the numeric display panel 88 and the test sequences will halt. The FIT operator then compares this address with the one that has been opera-tonally assigned to the LOT 24 being tested.
If the operator wishes to repeat this test, he presses RET. This test may be repeated as many times as is required before continuing with the sequence. The test sequence may be continued beyond the program halt by pressing the NEXT key.

11. Test sequences 33 and 77 will halt auto-magically at test 46. The data retrieved from the pulse initiator 56 will remain displayed while it is being observed by the FIT operator.

12. The test sogginess must be terminated by pressing NEXT. Test 50 will be performed and the sequence will be concluded.
STRUCTURE OF FIT
A block diagram of the field configuration terminal 26 is shown in Fig. 5. As can be seen therein, the FIT 26 is very similar to the interactive LOT 24 and DOT 29 and includes many components in common therewith.
The FIT 26 includes a key pad/display interface device 100 which may be a type IDEA device obtainable in 28 50,36~
coinmercial quantities from the Intel Corporation. The key pad/display interface device 100 is connected to the address bus 34 and data bus 36. Its input is connected to the key pad 84 and its output to display decoder and driver circuitry 102 which is connected -to the numeric displays and LED indicators. The display decoder and driver circuitry provides the function of converting the binary data supplied by the keyboard/display interface loo into seven segment code for the numeric display device and amplifying this seven segment out along with core-sponging activation outputs for the LED indicators Audi TV levels sufficient to drive the numeric display devices 88 and 94 and LED indicators Audi to full brilliance.
An analog multiplexer 104 is connected to the data bus 36 and address decode device 38. The multiplexer 104, under command of the microprocessor 27, selects one of a plurality of analog signal sources 106, each of which provides a different known level of analog signal and supplies the selected source as an analog test output signal.
A buffer 108 is also connected to the data bus 36 and to the address decode device 3g. The buffer 108 stores contact closure information from contacts of relays 58 from an associated LOT 24 or, aye, or DOT 29, and the status switches 90 on the panel of the FIT 26, and pro-vises such information onto the data bus when so commanded by the microprocessor 27.
The PI 50 of the FIT 26 also includes an INTO
ALSATIAN ENABLE output 110 which is connected to the INITIALIZATION ENABLE input line of an associated LOT 24 or DOT 29, such that when the FIT places the INITIALIZATION
ENABLE at ground potential, the associated LOT or DOT will accept an incoming address value as its assigned UNIQUE
address.
As can be seen, the AC purloin 101, INITIAL-RATION UNABLE output 110, output of the analog multiplexer 104, and relay contact inputs to the buffer 108 are all - -50,362 terminated in the connector plug 112 The plug 112 is compatible with output socket 72 of associated Lois 24 and aye, and DOT 29. When the plug 112 is inserted in the socket 72, AC power is supplied from the AC purloin S
through the associated terminal 24, aye, or 29 to the line 101 of the FIT 26. The INITIALIZATION ENABLE output 110 is similarly connected to the INITIALIZATION ENABLE input 59 of a terminal 24 or 29. Contacts of the relay 58 of the associated terminal 24, aye or 28 are connected to the buffer 108 and the analog test output 110 is connected to the multiplexer 74 of an associated DOT 29.
DESCRIPTION OF OPERATION OF FIT
A flow chart of the overall operation of the FIT
26 is shown beginning in figure PA. Instructions suffix client to perform the functions shown in the flow chart are stored in the ROM 44 of Figure 5.
Jo As soon as power is supplied to the FIT I the microprocessor 29 determines type of device the plug 112 is inserted. This information is obtained by reading shorting pins within the socket 72, which are different for each type of device. If a one-way LOT aye is con-netted to the FIT, program flow proceeds through point B
to operations calling for the entry of a Selected Block Address at 204 and of the relay configuration at 205.
This is accomplished using the key pad 84 as described herein before. Next a SHED LOAD command is generated in block 206 and transmitted as a carrier signal over the purloin. The connected LOT aye then deenergizes the relays. Since connections to the relay contacts pass through the socket 72 and plug 112, the status of the relay contacts is available to the buffer 108. At block 208, the microprocessor reads the status of the relays and then generates a RESTORE LOAD command which it transmitted as a carrier signal to the connected terminal aye to cause the relays to once again close their associated contacts.
At block 212 the status of the relay contacts is again read. The performance of the relays is then presented on the panel of the FIT by indicators 92b at block 214.

50,362 At block 216 a text is made -to determine if the status of the relays as determined by blocks 208 and 212 changed If not, program flow passes to block 218 wherein the NO-GO light Sue is illuminated. If the relay status is different, the GO indicator aye is illuminated at block 220. The program NEXT goes into a WAIT state looking for further input from the keyboard 84. If the REPEAT is pressed, program flow transfer to block 206 wherein the relay test is repeated for the same block address. If the RESET key is pressed, the program calls for a new operator entered value of selected block address at block 204.
! If it is determined at block 202 that an inter-active LOT 24 is connected to the FIT, program flow passes to block 300 in Figure 6B, where operator entered values of IRE address and Selected Block Addresses are caller for. Next, the FIT calls for an operator entered value indicating the number of relays to be tested followed by a request for the type of test desired As was explained before, this can include an installation, wherein a unique address is to be assigned to the connected terminal, a configuration check to see if the unique address of the connected terminal is the same as an address entered into the FIT by the operator, or a test to determine which unique address is currently assigned to the connected terminal. At block 306, the program determines which of the test modes is desired and branches accordingly. If a Code 77 ( READ AND TEST) has been entered, a program at block 308 generates commands to cause the connected ton-final to transmit the UNIQUE address programmed whereinto.
The FIT then displays the UNIQUE address received from the terminal to determine if the connected terminal responds correctly to an SPA command, and inhibits the terminal SPA
response. When a NEXT key is pressed, program control then transfers to block 324.
If a Code 33 TEST has been requested, program control transfers to block 316 of Figure 6B. If a Code 11 (INSTALLATION) has been requested, the INSTALL indicator Jo I

31 50,362 Ed is lighted and the INITIALIZATION ENABLE line is activated by placing it at ground potential. This causes the connected terminal to look for a message containing a UNIQUE address value. The connected terminal will then take a value so transmitted and accept that value as the UNIQUE address assigned to that terminal. At block 312, the FIT takes the operator-entered address value and sends a message containing that value over the purloin, where it is accepted by the connected LMTo In block 314, the lo INITIALIZATION ENABLE terminal is deactivated by the FIT
and a message transmitted to the connected LOT to retrains-mix the value of UNIQUE address now stored in nonvolatile RAM thereof. In block 318, the FIT determines if the address received from the connected LOT is the same as the address value entered by the operator at block 300 and also verifies the meter and relay configuration. If the received address is not the same, program control advances -to block 320 wherein the NO-GO LED aye is energized. The program then advances to a wait state at block 322. If the UNIQUE address received from the connected terminal is the same as the operator entered value, the FIT next generates a SHED LOAD command in block 324 and transmits this command over the purloin to the connected terminal.
The status of the relays of the connected terminal is then read at block 326. The program continues as shown in Fuller 5C at block 400 wherein a RESTORE LOAD command is generated and transmitted to the connected terminal. The FIT again reads the status of the relays of the connected terminal at block 402 and lights the appropriate GO or LOGO LED 92b for each relay.
At block 406 a check is made to determine if the status of the relays in block 326 is different from that of block 402. If the statuses are not different, this indicates that the SHED LOAD or LOAD RESTORE commands were not successfully executed and the appropriate NO-GO LED of test status indicator aye is energized. At block 410, the program enters a WAIT state looking for the next keyboard entry.

I 50,362 If the status of the relays as determined by blocks 326 and 402 is different, the SHED LOAD and LOAN
RESTORE commands were successfully executed, and the GO
LED of indicator aye is energized. Next, the HOT checks the DOT flag to see if the connected terminal is a DOT.
If so, program control branches to block 500 on fig. ED.
Otherwise the program continues at block 414 where the FIT
generates and transmits to the connected terminal a come mend for the registers of the associated wither meter 26 to be read by the connected terminal and transmitted back to the FIT. In block 416, the meter reading as received ! from the connected terminal is presented on the display 88. The program then enters a WAIT state at block 418.
Returning to block 202 on fig. PA, if the device connected to the FIT is a distribution and control terminal (DOT) 29 then the DOT flag is set at block 222. Program control transfers to block 300 of Figure 6B to perform the same tests as for the interactive terminal 24. At block 413 of Figure 6C, a check is made to determine if the DOT
flag is set. Since it is, program control transfers to block 500 of Figure ED. There the program calls for the operator to enter the code for the analog test source which is desired to be generated. At block 502, this analog source is connected to the connected load manage-mint terminal. The program then generates a READ ANALOG INPUT command and transmits it at block 504 to the con-netted terminal. The terminal then reads its analog input and transmits the digitized value back over the purloin to the FIT. At block 506, the FIT displays the received analog value and enters a wait state at block 508.
It can be seen that the disclosed embodiment provides electric utility system load management apparatus having increased capability and reliability over the prior art. While a preferred embodiment of the present invent lion has been disclosed hereinabove, it is to be understood that equivalent and alternative embodiments of this invent lion may be made without departing from the spirit and scope of the claims.

Claims (8)

Claims:

1. Distribution powerline carrier communication apparatus comprising:
a load management terminal connected to the powerline and deriving power therefrom, said load manage-ment terminal comprising a receiver coupled to the power-line for receiving a carrier signal imposed thereon and means connected to said receiver for controlling loads in response to said carrier signals, and a test terminal removably connected to said load management terminal and deriving operating power therefrom, said test terminal comprising a test transmitter coupled to the powerline for imposing carrier signals on the powerline, and means connected to said test transmitter for generating test commands to actuate said load control means and for modulating said commands onto carrier signals imposed on the powerline by said test transmitter, whereby said commands are transmitted from said test terminal to said load management terminal solely over the powerline and are received by said receiver to cause actuation of said load control means.

2. Apparatus as recited in claim 1 wherein the powerline runs through said load management terminal, and said test terminal is connected to the powerline through said load management terminal.

3. Apparatus as claimed in claim 2 wherein said load management terminal comprises a first multiple-circuit connector member and said test terminal comprises a second multiple-circuit connector member cooperating with said first connector member to removably establish a plurality of individual circuit connections between said test ter-minal and said load management terminal, said individual circuit connections including said connection from said test transmitter to said powerline.

4. Apparatus as recited in claim 1 wherein said load management terminal has a unique address whereby each of said load management terminals in a powerline carrier communication system can be individually accessed by an associated central control station, and said test command generating means comprises means for generating said unique address to cause said load management terminal to respond to commands generated by said test terminal.

5. Apparatus as recited in claim 1 wherein said load management terminal is an interactive terminal com-prising a load management terminal transmitter coupled to the powerline for transmitting carrier signals over said powerline in response to signals received by said receiver, and said test terminal comprises a test receiver coupled to the powerline for receiving signals transmitted by said load management terminal transmitter, and means for testing the accuracy of said load management terminal transmitter signals and for indicating the results of said signal testing to an operator.

6. Apparatus as recited in claim 5 wherein said test terminal comprises means for automatically generating a sequence of test signals for transmission to said load management terminal and for displaying a GO/NO-GO indica-tion to an operator to indicate the results of each test.

7. Apparatus as recited in claim 5 wherein said test terminal comprises means for receiving an operator-entered address value, said test terminal generating and transmitting a signal to a connected load management terminal to cause said load management terminal to generate and transmit a signal containing its unique address to said test terminal, said test terminal comprising means for indicating whether the unique address received from said connected load management terminal is the same as said operator-entered address.

8. Apparatus as claimed in claim 1 comprising a plurality of types of load management terminals each of which requires a separate set of tests to verify the proper operation thereof, and said test terminal comprises means for generating each of said test sets, means for recognizing the specific type of load management terminal connected thereto, means for permitting an operator to select one of said test sets to be performed by said test terminal, and means for indicating to an operator that the test set presently selected is the correct set for the type of load management terminal presently connected.