CA1200852A

CA1200852A - Catheter sensor and memory unit

Info

Publication number: CA1200852A
Application number: CA000415182A
Authority: CA
Inventors: Ate J. Meinema
Original assignee: Cordis Europa NV
Current assignee: Cordis Europa NV
Priority date: 1981-11-10
Filing date: 1982-11-09
Publication date: 1986-02-18
Also published as: US4858615A; NL193256C; NL9600011A; NL193256B; NL8105084A

Abstract

ABSTRACT
The sensor and memory unit (30, 92, or 94) includes a sensor assembly (34) having at least one sensor (48, 50 or 96) therein and a memory (18, 22, 70, 98) associated and fixed therewith. In one embodiment the memory (70, 98) is mounted in a memory module (38 or 90) which is connected by a multiconductor lead (40 or 88) to the sensor or sensors (48, 50 or 96). Also the sensor assembly (34) can be fixed in the distal end (36) of a catheter (32).
The sensor and memory unit (94) can be coupled to signal processing and conditioning circuitry (76, 176, 276) which can include a microprocessor (178) for proces-sing the sensor (96) signals and conditioning/correcting same based upon the information data retrieved from the memory (98).

Description

35~Z

CATHETER SENSOR AND MEMORY UNIT
Background of the Invention Field of the Invention The present invention relates to a sensor and mem-ory unit and more specifically to a catheter sensor andmemory unit for monitoring a chemical, physical or bio-logical parameter and for providing a standard output.
The unit includes a non-uniform sensor in a catheter and a memory connected thereto and containing correction in-formation which is supplied in parallel with the sensoroutput to signal conditioning and processing circuits to produce a standard output for the parameter(s) sensed.

Description of the Prior Art Sensors or sensor combinations that provide an elec-trically processable output signal are used in many fields for measuring and/or detecting a variety of phenomena.
These phenomena may, for example, be of a chemical, physi-cal or biological nature. As used herein, the term sen-sor can include a combinatiGn of cooperating sensors.
In the mass manufacture of sensors, an almost un-avoidable problem is encountered in that, from one speci-men sensor to another, the sensors have slightly different properties and exhibit a different behavior. This renders it difficult to compare accurately the results of measure-ments made with different sensors.
This drawback has been overcome in some instances by either applying very high standards in the production of the sensors, carrying out a very strict selection after production, and/or calibrating each sensor before use.
These methods are time consuming, either on the side of production or on that of the consumer, and expensive.
An user of a sensor who is aware of the problem of the different response characteristics of different sen-sors will try to use the same sensor all the time afterit has been calibrated. This, however, is often impossible in the field of medical sensors since certain sensors can 5;~

only be used once and/or have to be replaced after several uses thereof to avoid infection to a patient which can occur if a sensor is sterilizecl more than a few times.
Also, heretofore, a sensor which can be easily calibrated before use has not been readily available.
Furthermore, the response characteristics of one and the same sensor may vary in time, as a result of in-herent aging effects and/or as a result of its exposure to ambient conditions, such as temperature and pressure.
Heretofore, attempts have been made to develop an "ideal" sensor in order to eliminate the above drawbacks.
However, it is practically impossible to produce an "ideal"
or perfect sensor and this is especially so in the case of sensors which must be mass produced in larger numbers.
Additionally, it has been proposed to provide each sensor with an identification plater chained, for example, to the sensor, and showing some characteristics of the sensor. The user can then correct the sensor's output signals by means of the data on the identification plate.
Such correction may be effected, for example, by adjust-ing an electrical circuit arrangement which processes the sensor signals. This can be done, for example, by adjust-ing a potentiometer or thumb-wheel switches to effect the desired correction in the electrical circuit. This method is used, for example, in Fleisch Flow Transducers.
However, this method is not always effective since errors may occur in correlating a plate with a sensor, both during production, because, for example, the identi-fication plates may be interchanged, and in use, because an identification plate is misread or the electrical cir-cuit is maladjusted.
Such interchange of identification plates is not an uncommon event and periodically occurs in the mass pro-duction of sensors.
Furthermore, the adjustment of an electrical cir-cuit by hand is a cumbersome job and lowers the market appeal of such sensors provided with identification plates.
In some sensor applications, such as, for example, 1~0~

in the medical field, it is of great importance that the risk of error be as low as possible. As a result, the manual adjustment of equipment coupled to sensors on the basis of data on an identification plate is highly unde-sirable.
Furthermore, even if manufacturing techniques are perfected to such an ex-tent that certain types of sensors can be made sufficiently "ideal", it is yet often desir-able to record specific unique information associated with a particular sensor in such a manner that when the sensor is used such uni~ue information is immediately available without the risk of errors.
Such unique information may comprise, for example, the type of sensor, or type number, serial number, datè
of production, or safe use life of the sensor.
Consequently, an identification plate sensor combin-ation as described above although useable in the medical field, still has the inherent drawbacks described above.
Still further it has been proposed in U.K. patent 20 application No. 2,065,890 for: SENSOR SYSTEM WITH NON-LINEARITY CORRECTION by-Felix J. Houvig, published July 1, 1981 to provide a sensor system comprising a fluid tight housing having a fluid pressure inlet portion and the sensor is mounted to an electronic component housing for electronic circuitry including sensor amplifying cir-cuits, a power supply, a transistor switch, a shift reg-ister and a PROM. A signal isolation interface circuit is fixed to one side of the electronic component housing for connecting the electronic component housing and elec-tronic circuitry therein to a microprocessor.
The PROM in this sensor system is programmed with correction control data to compensate for non-linearity and/or perhaps, other characteristics in the sensor out-put.
As will be described in greater detail hereinafter, the sensor and memory unit of the present invention differ from the sensors or sensor systems described above by pro-S'~

viding an integral, unitary sensor and memory combination unit where information regarding the characteristics of the sensor or sensor-memory combination are permanently recorded in ~he memory and the sensor and memor~ are in-dissolubly coupled together. The recorded informationcan be automatically and directly read and retrieved by separate electronic processing circuitry.
Also the sensor and memory unit of the present in-vention preferably includes a catheter for carrying the sensor therein, such as at one end thereof, and for pro-~iding a conduit for wire conductor connections between the sensor or sensors in the catheter and the memory fixed to the catheter. Such sensor and memory unit is particularly adapted for use in the medical field.
More specifically with respect to the sensor sys-tem disclosed in U.K. patent application No. 2,065,890 such sensor system describes a method for correcting an output signal of an electronic signal conditioning cir-cuit where memory information may be used for non-ideal transducer chcaracteristics, such as non-linearity, which is reflected in the output signal of the electronic signal conditioning circuit. However, an ideal linear transducer may have sensitivity deviation from nominal sensitivity specifications and the U.K. patent applica-25 tion No. 2,065,890 does not indicate how these differen-ces in sensitivity from nominal specifications can be treated.
As described in further detail hereinafter the sensor and memory unit of the present invention are util-ized in a system where an ideal transducer is assumed, i.e., a perfectly linear transducer. However, all sen-sors built deviate from the nominal specification estab-lished therefor. In the memory of the present invention the actual specification of the ideal transducer (for example, pressure sensitivity, offset, temperature sen-sitivity) are stored.
In a sensor system including signal processing and conditioning circuitry that can be coupled to the sensor 8S~

and memory unit of the present invention, the information data stored in the memory is decoded and the characteris-tics of the signal conditioning circuitry associated with the microprocessor are changed (for example, the amplifi-cation factor or offset are changed). As a result, theoutput signal from ~he signal conditioning circuitry al-ways will be the same as for a sensor or transducer with nominal specification for any sensor and memory unit of the present invention that is coupled into the sensor sys-tem. Stated otherwise, the final output signal is stan-dard for every transducer whereas in the sensor system dis-closed in U.K. patent application No. 2,065,890, the am-plitude of the signal depends on transducer sensitivity.
Also the memory can contain direct data for the ad-justment of the signal processing and conditioning cir-cuitry instead of data concerning the sensor character-istics.
~ nally, and what has been explained above, the sen-sor and memory unit of the present invention is just that, namely a sensor and memory unit alone without any signal processing and conditioning circuitry, so as to provide a simple and single, compact, unit which can be incorporated into a catheter for use in the medical field and which can be detachably coupled to any one of several types of siqnal processing and conditioning circuits.

35;~

DISCLOSURE OF INVENTION
According to the invention there is provided a catheter sensor and memory unit comprising a c~theter, a sensor assembly mounted at the distal end of said catheter r and a memory module connected to the proximal end of said catheter and having a memory therein contain-ing characteristic data of a sensor or sensors in said sensor assembly.
Also according to the invention there is provided an integral sensor and memory unit comprising a sensor assembly having one or more sensors mounted therein, a memory module having a memory mounted therein containing characteristic data for the sensor or sensors in said sensor assembly and a multiconductor lead connected be-tween said sensor assembly and said memory module.
Further according to the invention there is pro-vided a method for manufacturing sensors or sensor com-binations that provide an electrically processable output signal, comprising the steps of: recording the charac-teristic data for each sensor or sensor combination inan automatically and directly electronically readable permanent memory; and indissolubly connecting the memory to the sensor or sensor combination.
Still further according to the invention there is provided a sensor or sensor combination that provides an electrically processable output signal combined with a directly and electronically readable permanent memory for recording the characteristic data of the sensor or sensox combination and means for indissolubly connecting the memory to the sensor or sensor combination.

' )bl5~

BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic circuit diagram of a prior art sensor incorporated into a Wheatstone bridge.
F ig. 2 is a perspective view of a prior art sen-sor provided with an iden-tification plate.
Fig. 3 is a plan view of a bar code defining the memory of one embodiment of a sensor and memory unit of the present invention.
Fig. 4 is a resistance/binary table defining the memory of a sensing and memory unit of another embodiment of the present invention.
Fig. 5 is a perspective view of a catheter sensor and memory unit of still another embodiment of the pres-ent invention.
Fig. 6 is a sectional view of the sensor assembly at the end of the catheter shown in Fig. 5.
Fig. 7 is a sectional view of the memory module coupled to the catheter shown in Fig. 5.
Fig. 8 is a sectional view of the memorv module sho~n in Fig. 7 and is taken along line 8-8 of Fig. 7.
Fig. ~ is a plan view of an in-line pressure sen-sor, catheter and memory unit of yet another embodiment of the present invention.
; Fig. 10 is a schematic circuit diagram of one type of signal conditioninq circuit to which a sensor and mem-ory unit of the present invention can be detachably coup-led to form a sensor system.
Fig. 11 is a schematic circuit diagram of another type of signal conditioning circuit to which a sensor and memory unit of the present invention can be detachably coupled to form a sensor system.
Fig. 12 is a schematic circuit diagram of still an-other type of signal conditioninq circuit to which a sen-sor and memory unit of the present invention can be detach-ably coupled to form a sensor system.

3,5;~

DESCRIPTION OF TEIE PREFERRED EMBODIMENTS
Referring now to the drawinqs in greater detailthere is illustrated in Fi~. 1 a Wheatstone bridqe 10 comprising four resistors Rl to R4. These resistors form a sensor 10 which, for example, may be a pressure sensi-tive sensor. Such circuit arrangements are well known.
According to known and conventional methods of production, an output voltage Vo is measured, and one or more suitable resistors Rx are selected and mounted in the bridge 10, in order that bridge equilibrium and the sen-sitivity of the sensor 10 constituted by the bridge 10 may be adjusted in any desired way.
In this embodiment a series of sensors 10 are pro-duced which, it is true, are all equal to the extent pos-sible, but whose sensitivity are generally that of the sen-sor 10 having the lowest sensitivity.
The individual adjustment of each sensor 10 is ex-pensive and time consuming, and in addition re~uires a large stock of resistors for the resistor Rx.
In Fig. 2 is illustrated a sensor 12 provided with an identification plate 13 which in the case shown is at-tached to the sensor by a cord or chain 14. The sensor 12 can be a Fleisch Flow Transducer. In the manufacture of such sensors 12, no effort is made to produce stan-dard sensors 12. Instead, correction of the sensor 12 characteristics is done by the user, who adjusts equip-ment (not shown) for processing the output signals from a partlcular sensor 12 on the basis of the data carried by the identification plate 13 therefor. The disadvan-tages of this method of correction have been describedabove.
According to the teachings of the present invention, no attempt is made to produce sensors as uniform as possi-ble by trimming or other adjustment. On the contrary, the characteristic properties of each sensor with regard to ambient effects, sensitivity and the like are measured.
Such a measurement has been conventional in the past for 35;~

purposes of quality control.
Further according to the teachings of the present invention, the resulting measurements and/or other data uniquely associated with the sensor are not specifled on an identification plate, but joined with the sensor in such a manner that it is automatically processed by the equipment coupled to the sensor without any initial adjust-ing operations being required from the user.
For thls purpose, the measurement data and/or other data are stored in a memory, the contents of which can be processed automatically and electronically. The memory is indissolubly connected to the associated sensor. For this purpose the memory may be incorporated, for example, in the sensor housing or in the sensor's connector. It is con-ceivable that, for certain uses, the memory is constitutedby a specific configuration of, or specific connection of, connector pins, or by a specific mechnical treatment of the connector housing.
A special configuration of connector pins can be realized, for example, by placing the pins in a specific pattern and/or machining one or more pins house-key fashion.
The processing equipment then will include a com-plementary connector suitable for all possible configura-tions, and connected in such a manner that the information stored in the connector is processed in the proper manner.
Alternatively, means for detecting the mechanical treat-ment of the connector housing are provided.
Moreover, a suitable memorv can be realized, for example, by a magnetic card, a bar code marked on a car-rier, a resistance code, or a PROM tprogrammable readonly memory).
The processing equipment must, of course, be adap-ted to the type of memory being used. Such an adapta-tion, hcwever, should not present any problems to those skilled in the art.
In Fig. 3 is shown an example of a bar code 18 em-bodying the characteristics of a sensor with which it is associated and for which it constitutes the memory of one embodiment of a sensor and memory unit constructed accord-ing to the teachings of the present invention. Such a bar code 18 is preferably marked on a connector housing, e.g., printed, engraved or impressed.
In Fig. 4 is shown a table 22 of resistance/binary code. Each resistor or combination of resistors R corres-ponds to a binary number sPecified in the table 22 stored in processing equipment. The processing equipment may com-prise a microprocessor, whish, under the control of the bi-nary number assoclated with a given resistance code, ef-fects certain corrections with regard to the sensor signal.
The resistance/binary code may not be adequate, however, if a substantial amount of data concerning the sensor is to be stored, since large quantities of resistors must be kept in stock. For minimal data, however, the resistance code is quite suitable.
The use of a PROM as a memory appears to be very suitable. PROM's are commerc;ally available with very small dimensions but with a relatively large memory capa-city of 256 bits or more.
A PROM suitable for the purposes of the present in-vention is, for example, the IM 5600-5610 series of Intersil, Inc.
During the production of sensors, a PROM can be automatically programmed by a computer-controlled test-ing system as used in the production of large numbers.
Furthermore, as stated before, the tvpe of sensor and other unique information, such as type num~er, serial number, production date, safe service life, etc. can be recorded in the memory, which offers the possibility of designing processing equipment suitable for various types of sensors.
In this wav, there is provided with the sensor and memory in conjunction with a deciphering (microprocessor) circuit and signal conditioning circuit a multi-purpose measuring and detecting system which requires no user calibration thus enhancinq its consumer appeal and which l~V~35~Z

minimizes r if not altogether eliminates user errors in ca~ibration and use. Also such a sensor and memory unit can readily be combined with a catheter to provide one preferred embodiment of the present invention, namely a catheter sensor and memory unit 30 as will now be de-scribed in detail in connection with the following de-scription of Figs. 5-12.
As shown in Fig. 5, the catheter sensor and memory unit 30 has a sensor assembly 34 at one end 36 of the catheter 32 and a memory module 38 is coupled by a multi-conductor lead 40 through a three way connector 42 to the other end 44 of the catheter 32. Also a coupling 46 is provided at the end 44 of the catheter 32 for coupling same to a fluid delivery or withdrawal system (not shown).
As shown in Fig. 6, the sensor assembly 34 includes a tube 47 having two sensors 48 and 50 therein. The sen-sor 48 is a temperature sensor bulb and the sensor 50 can be a pressure sensor or an electrode for in vivo measure-ment of body fluids. The temperature sensor bulb 48 is surrounded by thermal conducting material 52 packed in the end of the tube 47 which is sealed off by an end plug 54.
The tube 47 has a hole 56 therein for sensing pres-sure or for measuring body fluids. In this respect, in-side the tube 47 is a carrier 58 mounting the sensor or electrode 50 beneath the hole 56. A sealing material 60 is provided in the tube 47 around the sensor or electrode 50 and the hole 56.
Where body fluids are to be measured a membrane (not shown) formed of hydrogel can be positioned across the hole or aperture 56 so as to form an ion diffusion barrier between body fluids to be measured and electro-lyte material within the tube 47 and in conatct with electrode 50.
Several leads or insulated conductors such as con-ductor 61 from the temperature sensor bulb 48 and a con-ductor 62 from the sensor or electrode 50 extend rear-wardly from the sensor assembly 34 through the catheter ~v~s;~

32 to the three way connector 42 where the plurality of wire conductors 61 and 62 then branch off into the multi-con~uctor cable 4~ lead~ny to the memory module 38.
In the distal end 36 of the catheter 32 there is provided an opening 64 which communicates with a passage-way 66 within the catheter 32. This passageway 66 extends to and through the connector 42 through the proximal end 44 of the catheter 32 to the coupling 46 and facilitates the insertion or withdrawal of fluids through catheter 32 to or from the opening 64.
Where the sensor 50 is an electrode for measuring body fluids, the openiny 64 can ~e positioned so as to open adjacent the membrane of hydrogel so that liquid ex-iting therefxom can provide a flushing action across the - 15 surface of the hydrogel membrane.
As shown in Figs. 7 and 8, the multiconductor lead 40 extends to and into a housing 68 of the memory module 38. As shown, a memorv 70 such as a PROM is mounted with-in the housing 68 on a circuitboard. Wire conductors suc~l as conductors 61 and 62 within the multiconductor lead 40 connect the sensors 48 and 50 to connector pins 72 sit-uated within a connector housing 74 fixed to the housing 68. The PROM 70 is also connected to the connector pins 72.
The connector pins 72 within connector housing 74 can then ~e easily connected to a mating connector socke' module associated with signal processing and conditioning circuitry 76 (Fig. 10).
In Fig. 9 is shown a three way coupling member or 30 flow cell 80 which has in-line nozzles 82 and 84 on either side thereof and a sensing chamber 86 therein. The sens-ing chamber 86 has at least one sensor therein which is coupled by a lead 88 to a memorv module 90 similar to or identical to the memory module 38 to form another embodi-ment of a sensor and memory unit 92 constructed in accord-ance with the teachings of the present invention. The sensor can be a flow rate sensor or a pressure sensor.

U85~Z

Referrinq now to Fig. 10 there is illustrated there-in a signal processing and conditioning circuit 76 which is coupled to a sensor and memory unit 94 constructed in accordance with the teachings of the present invention and which for example can be the catheter sensor and memory unit shown in Fig. 5.
The sensor and memory unit 94 includes a sensor 96 and a memory 98. The circuit 76 is adapted to be coupled by means of connector pins 101-105 to the sensor and mem-ory unit 94 as shown. The circuit 76 is adapted to measureand detect the characteristic data in the memory 98 asso-ciated with the sensor 96 and to process such data in the circuit 76.
The data is typically stored in digital form in the memory 98 associated with the sensor 96 and is conver-ted in the siqnal processing and conditioning circuit 76 into voltages, currents or gain factors and such voltages, currents or gain factors are utilized in adjusting cir-cuit components in the signal processinq and conditioning circuit 76.
If the sensor and memory unit 94 is of the type il-lustrated in Fig. 5, the sensor 96 is housed or mounted within the distal end of a catheter. Electrical conduc-tors withïin the catheter then connect the sensor 96 to connector pins 101-103 in a connector housing (not shown).
The memory 98 associat~d with the sensor 96 can then be mounted in a connector housing (not shown) such as the housing 68 shown in Fig. 5 and connected to connector pins 104 and 105 as shown.
A voltage bus 106 is connected to connector pin 101 for supplying voltage to tne sensor 96. If necessary, such voltage can also be supplied to the memory 98.
The sensor 96 can be of the type which will provide a temperature sensor signal to connector pin 102 and a pressure sensor signal to pin 103 which pins 102 and 103 are connected, respectivelv, to a first amplifier 108 and a second amplifier 110. As shown, the output of the am-~v~s~

plifier 108 which receives the temperature sensor signal is combined with -the pressure sensor signal supplied to the second amplifier 110 for controlling the adjustment of the second amplifier 110. Here we have temperature dependent pressure sensor signals and pressure dependent temperature sensor signals.
The adjustments of the amplifiers 108 and 110 are further controlled by the data read from the memory 98 and supplied to connector pin 104. This ad~ustment is effected by a clock 112. In this respect, the clock 112 is coupled via a bus 114 to the terminal pin 105 for sup-plying a clock pulse to the memory 98 connected to the connector pins 104 and 105.
As shown, the clock 112 supplies a clock pulse to the bus 114 which then supplies the clock pulse to the mem-ory 98 and to clock inputs 116, 118, 120 and 122 of latch-ing circuits 126, 128, 130 and 132. ~he data supplied to the connector pin 104 from the memory 98 is placed on a bus 134 which is connected to data inputs 136, 138, 140 and 142 of the latching circuits 126, 128, 130 and 132.
As a result, each time a clock pulse is outputted by the clock 112, the data on the bus 134 from the memory is in-putted to the respective latching circuits 126, 128, 130 and 132.
The latching circuits 128 and 132 then output a gain factor signal to the amplifiers 108 and 110 respec-tively as shown.
In a similar manner, the correction data clocked into the latches 126 and 130 are outputted to respective digital to analog converter circuits 146 and 150 which then output a bias or offsetting signal to the input of ampli-fiers 108 and 110 respectively as shown.
A corrected analoo sensor signal then ultimately appears at output 160 of the second amplifier 110 and can be processed further in a suitable manner.
In Fig. 11 there is show a different t~pe of sig-nal processin~ and conditioning circuit 176 which can be coupied to the sensor and memory unit 94 as shown. Here the circuit 176 includes a microprocessor 178 which is coupled by an address bus 180 and d~ta bus 181 to a buf-fer cir~uit 182 tha; is connected to connector pins 104 and 105 for retrieving information data from the memory 98. The microprocessor 178 processes the data retrieved from the memory 98 and then causes appropriate adjustment of the second amplifier 110. In this respect, the micro-processor 178 supplies address signals to the address bus 180 which controls latch circuits 184 and 186. Latch cir-cuit 184 supplies a digital signal to a D/A converter 185 which outputs an analog signal that is input to second amplifier 110 as an offset signal. The latch 186 supplies a gain adjust or gain factor signal directly to the second amplifier 110 as shown. The output signals from the ampli-fiers 108 and 110 are then digitized by an A/D converter 190 that has an output coupled to another latch circuit 192.
The microprocessor 178 will cause the latch circuit 192 to output a corrected digital sensor signal to the data bus 181. A D/A converter 196 is coupled to the ad-dress bus 180 and the data bus 181 and is operated by the microprocessor 178 to output at output 206 a corrected analog sensor signal converted from the signal supplied to the data bus 181 by the latch 192.
Referring now to Fig. 12 there is illustrated there-in a modified signal processing and conditioning circuit 276 which is similar to the circuit 176 except that in this circuit 276 the latches 184 and 186 and the D/A con-verter 185 are omitted and the amplifiers108 and 110 have a fixed amplification setting. In this modified circuit, the data stored in the memory 98 is not used by the micro-processor 178 for adjusting the settings of amplifier 110.
Rather, the data stored are used as computational magnitudes for processing the sensor signal.
The information stored in the m~mory 98 ~an be util-ized to process the sensor signals supplied to the ampli-fiers 108 and 110. Alternatively, the information data in the memory 98 can be passed directly to output terminals 5~

282 and 294 as shown in Figs. ll and 12, after conversion, if necessary, into a form suitable for further processing, such as, for example, for being displayed on ~ display de-vice (not shown).
It will be understood from the foregoing descrip-tion that the teachings of the present invention can be utilized in different ways in a method for manufacturing sensors or sensor combinations together with the recording of characteristic data for individual sensor or sensor combinations in an automatically and directly electrical-ly readable permanent memory. Also according to this method, the memory is indissolubly connected to the sensor or sensor combination.
Obviously, the particular data stored, the magnitude to be corrected and the number of corrections will depend, of course, upon the particular sensor utilized. In this respect, the sensor or sensor combination can include a flow rate sensor, a pressure sensor, a temperature sen-sor, an electrolyte sensor or a chemical sensor.
Moreover, modifications can be made to the various el~odiments of the present invention described above with-out departing from the teachings of the invention. For I example, the chamber 86 within the three way coupling mem-¦ ber 80 can have a flow rate sensor mounted therein instead ¦ 25 of a pressure sensor.
Also it will be apparent that the sensor and memory unit of the present invention has a number of advantages, some of which have been described above and others of which are inherent in the invention. Specifically, the sensor 1 30 and memory unit of the present invention can be disposable sensors, can be mass produced, and can be utilized in the medical field or in the airplane industry. Accordingly, the scope of the invention is only to be limited as nec-essitated by the accompanying claims.

Claims

PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A catheter sensor and memory unit comprising a catheter, a sensor assembly mounted at the distal end of said catheter, and a memory module connected to the prox-imal end of said catheter and having a memory therein con-taining characteristic data of a sensor or sensors in said sensor assembly.

2. The unit of claim 1 wherein said memory module includes a connector housing having connector pins mount-ed therein and wherein said catheter has electrical con-ductors therein extending from said sensor assembly to said memory module.

3. The unit of claim 2 wherein said sensor and said memory are connected to said connector pins in said connector housing.

4. The unit of claim 1 wherein said sensor assem-bly includes a rate of flow monitor.

5. The unit of claim 1 wherein said sensor assem-bly includes a pressure sensor.

6. The unit of claim 1 wherein said sensor assem-bly includes a temperature sensor.

7. The unit of claim 1 wherein said sensor assem-bly includes a body fluid sensing electrode for making electrolyte measurements.

8. The unit of claim 1 wherein said sensor assem-bly includes a sensor for making chemical measurements.

9. The unit of claim 1 wherein said catheter has an aperture in the distal end thereof and a passageway therethrough for the delivery or withdrawal of fluids to or from said aperture and has fluid coupling means at the proximal end thereof for coupling said passageway to a fluid delivery or withdrawal device.

10. The unit of claim 9 including a three way coupling device mounted to said catheter adjacent the proximal end thereof, said memory module being connected to said three way coupling device by a multiconductor lead having conductors which extend through the coupling de-vice and said catheter to said sensor assembly and said passage means extending through the coupling device and the proximal end of said catheter to said fluid coupling means.

11. The unit of claim 10 wherein said memory module includes a connector housing having connector pins there-in and one or more sensors in said sensor assembly, said memory and said sensor or sensors being connected to said connector pins.

12. The unit of claim 1 wherein said memory is a PROM.

13. An integral sensor and memory unit comprising a sensor assembly having one or more sensors mounted there-in, a memory module having a memory mounted therein con-taining characteristic data for the sensor or sensors in said sensor assembly and a multiconductor lead connected between said sensor assembly and said memory module.

14. The unit of claim 13 wherein said sensor assem-bly is mounted at the end of a catheter.

15. The unit of claim 13 wherein said sensor assem-bly is mounted in a flow cell.

16. The unit of claim 15 wherein said flow cell in-cludes a housing having a chamber therein and in-line noz-zles extending from opposite ends of said housing for be-ing series connected in a fluid conduit.

17. The unit of claim 16 wherein said sensor assem-bly in said flow cell includes a f low rate sensor.

18. The unit of claim 16 wherein said sensor assem-bly in said flow cell includes a pressure sensor.

19. The unit of claim 13 wherein said memory module includes a connector housing having connector pins mounted therein for facilitating coupling of said sensor and memory unit to a signal processing and conditioning circuit.

20. A method for manufacturing sensors or sensor combinations that provide an electrically processable output signal, comprising the steps of: recording the characteristic data for each sensor or sensor combination in an automatically and directly electronically readable permanent memory; and indissolubly connecting the memory to the sensor or sensor combination.

21. The method of claim 20 wherein the characteris-tics of each sensor or sensor combination are recorded in the associated memory.

22. The method of claim 20 wherein the sensor or sensor combination is mounted in a housing and said mem-ory is also mounted in said housing.

23. The method of claim 20 wherein the sensor or sensor combination comprises means for connecting the sensor to processing equipment for processing the sensor signals and said memory is carried by said connecting means.

24. The method of claim 20 wherein the sensor or sensor combination comprises a connector for coupling the sensor to processing circuitry for processing the sensor signals and the connector itself is used as the memory.

25. The method of claim 24 wherein the memory func-tion of the connector is obtained by mechanical treat-ment of the housing for the connector.

2 6. The method of claim 24 wherein the memory func-tion of the connector is obtained by a special configura-tion of the ends of the connector.

27. The method of claim 24 wherein the memory func-tion is obtained by a special way of connecting connector pins of the connector.

28. The method of claim 22 wherein said memory is realized by a bar code marked on said housing.

29. The method of claim 23 wherein said memory is realized by a bar code carried by said connecting means.

30. The method of claim 22 wherein said memory is realized by a resistor combination corresponding to a code.

31. The method of claim 22 wherein said memory is a magnetic card.

32. The method of claim 22 wherein said memory is a PROM.

33. The method of claim 21 wherein the characteris-tics of each sensor or sensor combination are measured by means of a computer controlled signal processing and con-ditioning circuit.

34. The method of claim 20 further comprising the steps of utilizing signal processing and conditioning cir-cuitry for processing output signals of the sensor or sensor combination and wherein output signals from the sensor or sensor combination are processed through at least a first signal path in said signal processing and conditioning circuitry and through a second signal path having means for detecting and processing the information recorded in the memory and means for effecting a transmis-sion function of the first signal path in dependence upon the information recorded in the memory.

35. The method of claim 34 wherein said signal processing and conditioning circuitry utilizes a micro-processor for the detection and processing of the infor-mation recorded in the memory and for effecting the trans-mission function of the first signal path.

36. The method of claim 20 including the step of utilizing signal processing and conditioning circuitry for processing the output signals from the sensor or sen-sor combination and wherein said signal processing and conditioning circuitry includes a microprocessor to which the information recorded in the memory is supplied and which, in dependence upon such retrieved information, processes the sensor signals and supplies the conditioned or corrected sensor signals to an output terminal.

37. A sensor or sensor combination that provides an electrically processable output signal combined with a directly and electronically readable permanent memory for recording the characteristic data of the sensor or sensor combination and means for indissolubly connecting the memory to the sensor or sensor combination.

38. The sensor or sensor combination of claim 37 being mounted in a housing and said memory is also mounted in said housing.

39. The sensor or sensor combination of claim 37 comprising means for connecting the sensor to processing equipment for processing the sensor signals and wherein said memory is carried by said connecting means.

40. The sensor or sensor combination of claim 37 comprising a connector for coupling the sensor to proces-sing circuitry for processing the sensor signals and the connector itself is used as the memory.

4 1. The sensor or sensor combination of claim 40 wherein the memory function of the connector is obtained by mechanical treatment of the housing for the connector.

42. The sensor or sensor combination of claim 40 wherein the memory function of the connector is obtained by a special configuration of the ends of the connector.

43. The sensor and sensor combination of claim 40 wherein the memory function is obtained by a special way of connecting connector pins of the connector.

44. The sensor and sensor combination of claim 38 wherein said memory is realized by a bar code marked on said housing.

45. The sensor and sensor combination of claim 39 wherein said memory is realized by a bar code carried by said connecting means.

46. The sensor and sensor combination of claim 39 wherein said memory is realized by a resistor combination corresponding to a code.

47. The sensor and sensor combination of claim 39 wherein said memory is a magnetic card.

48. The sensor and sensor combination of claim 39 wherein said memory is a PROM.

49. The sensor and sensor combination of claim 37 wherein the characteristics of each sensor or sensor com-bination are measured by means of a computer controlled signal processing and conditioning circuit.

50. A sensor system comprising the sensor or sen-sor combination of claim 37 and signal processing and con-ditioning circuitry for processing output signals from the sensor or sensor combination and said circuitry being capable of taking output signals from the sensor or sen-sor combination and processing them through at least a first signal path in said signal processing and condition-ing circuitry and through a second signal path having means for detecting and processing the information recorded in the memory and means for effecting a transmission function of the first signal path in dependence upon the informa-tion recorded in the memory.

51. The sensor system of claim 50 wherein said sig-nal processing and conditioning circuitry utilizes a mi-croprocessor for the detection and processing of the in-formation recorded in the memory and for effecting the transmission function of the first signal path.

52. A sensor system comprising the sensor or sensor combination of claim 37 and signal and processing and con-ditioning circuitry for processing the output signals from the sensor or sensor combination and said circuitry com-prising a microprocessor which,in dependence upon the retrieved information from the memory,processes the sen-sor signals and supplies the conditioned and/or corrected sensor signals to an output terminal.

53. A method for manufacturing sensors or sensor combinations that provide an electrically processable out-put signal, comprising the steps of: recording data for adjusting signal processing and conditioning circuitry to which the sensor or sensor combination can be connected in an automatically and directly electronically readable permanent memory; and indissolubly connecting the memory to the sensor or sensor combination.

54. A catheter sensor and memory unit comprising a catheter, a sensor assembly mounted at the distal end of said catheter, said sensor assembly comprising sensor means for sensing an electrical, chemical or physiological parameter in a body, and non-volatile memory means, which are permanently coupled to said sensor means and which contain initializing information data relative to the particular sensor means, such as offset data, amplification data, etc., for supplying said initializing information data to information processing means so that when such information processing means are coupled to said sensor and memory unit and energized, the initializing information data immediately will be received by processing circuitry within the information processing means which is then initialized so that said information processing means can treat the combination of said sensor means and said memory means as an ideal sensor and provide an output signal, relative to a signal generated by said sensor means, equivalent to the output signal which would be obtained from perfect sensor means.

55. The unit of claim 54 including a memory module which has said memory means therein and which is connected to the proximal end of said catheter.

56. The unit of claim 55 wherein said memory module includes a connector housing having said memory means therein and connector pins mounted therein and wherein said catheter has electrical conductors therein extending from said sensor means to said memory module.

57. An integral sensor and memory unit comprising a sensor assembly having sensor means mounted therein, a memory module, non-volatile memory means for recording initializing information data relative to the particular sensor means, such as offset data, amplification data, etc., and for supplying said initializing information data to information processing means so that when such information processing means are coupled to said sensor and memory unit and energized, said initializing information data immediately will be received by processing circuitry within said information processing means which is then initialized so that said information processing means can treat the combination of said sensor means and said memory means as an ideal sensor and provide an output signal, relative to a signal generated by said sensor means, equivalent to the output signal which would be obtained from perfect sensor means, said memory means being mounted in said memory module and being permanently coupled to said sensor means, and a multiconductor lead connected between said sensor assembly and said memory module.

58. A sensor and memory unit comprising sensor means that provide an electrically processable output signal, directly and electronically readable non-volatile memory means for recording the initializing information data relative to the particular sensor means, such as offset data, amplification data, etc., and for supplying said initializing information data to information processing means so that when such information processing means are coupled to said sensor and memory unit and energized, the initializing information data immediately will be received by processing circuitry within said information processing means which is then initialized so that said information processing means can treat the combination of said sensor means and said memory means as an ideal sensor and provide an output signal, relative to a signal generated by said sensor means, equivalent to the output signal which would be obtained from perfect sensor means, and means for permanently connecting said memory means to said sensor means.

59. The sensor and memory unit of claim 58 comprising means for connecting said sensor means to processing equipment for processing signals from said sensor and memory unit and wherein said memory means are carried by said connecting means.

60. A sensor system comprising: at least one sensor, said at least one sensor being capable of providing an electrically processable output signal;
memory means associated with said at least one sensor and containing initializing information data, such as offset data, amplification data, etc., relative to said at least one sensor means connected with said at least one sensor for processing the sensor output signal to obtain a sensor system output signal; and means for reading out said initializing information data from said memory means, said memory means including a non-volatile memory having the initializing information data relative to said at least one sensor recorded therein and being permanently coupled to said at least one sensor, and said processing means comprising signal processing and conditioning circuitry capable of taking output signals from said at least one sensor and processing them through at least a first signal path in said signal processing and conditioning circuitry and of taking said initializing information data from said memory means and processing such initializing information data through a second signal path having means for detecting and processing said initializing information recorded in said memory means and means for influencing the processing function of the signals from said at least one sensor via said first signal path in dependence upon the initializing information data recorded in said memory means.

61. The sensor system of claim 60 wherein said signal processing and conditioning circuitry includes and utilizes a microprocessor for the detection and processing of the information recorded in said memory means and for effecting the transmission function of said first signal path.

62. The sensor system according to claim 60 wherein said at least one sensor is mounted in a distal end of a catheter.

63. The sensor system according to claim 60 wherein said signal processing and conditioning circuitry includes and utilizes a microprocessor for the detection and processing of said initializing information data recorded in said memory means in order to influence the transmission function via the first signal path and in dependence upon the initializing information data retrieved from said memory means for processing and conditioning said sensor signals and for supplying the conditioned sensor signals to an output terminal.

64. A catheter sensor and memory unit comprising a catheter, a sensor assembly incorporated in said catheter, said sensor assembly consisting of sensor means at the distal end of said catheter for sensing an electrical, chemical or physiological parameter in a body, and non-volatile memory means, which are permanently coupled to said sensor means and which contain information data relative to the particular sensor means for use in setting up information processing means for processing signals from said sensor means, such as offset data, amplification data, etc., and for supplying said information data to the information processing means so that when such information processing means are coupled to said sensor and memory unit and energized, the information data immediately will be received by processing circuitry within the information processing means which is then set up so that said information processing means can treat the combination of said sensor means and said memory means as an ideal sensor and provide an output signal, relative to a signal generated by said sensor means, equivalent to the output signal which would be obtained from perfect sensor means.

65. The unit of claim 56 wherein said memory module includes a connector housing having only said memory means and said connector means mounted therein, said connector means includes connector pins mounted in said housing and connected to said memory means and said catheter has electrical conductors therein extending between and connected to said sensor means and said connector pins.

66. The unit of claim 9 including a three way coupling device mounted to said catheter adjacent the proximal end thereof, a multi-conductor lead and a memory module including a connector housing having connector pins therein, said memory means being mounted in said connector housing and being connected to said connector pins, and said multi-conductor lead being connected to said connector pins and extending from said memory module through said three way coupling device and through said catheter to said sensor means to which said lead is also connected, and said passage means extending through said catheter and said three way coupling device to said fluid coupling means.

67. An integral sensor and memory unit consisting of a sensor assembly having sensor means mounted therein, a memory module, non-volatile memory means for recording information data relative to the particular sensor means for use in setting up information processing means for processing signals from said sensor means, such as offset data, amplification data, etc., and for supplying said information data to the information processing means so that when such information processing means are coupled to said sensor and memory unit and energized, said information data immediately will be received by processing circuitry within said information processing means which is then set up so that said information processing means can treat the combination of said sensor means and said memory means as an ideal sensor and provide an output signal, relative to a signal generated by said sensor means, equivalent to the output signal which would be obtained from a perfect sensor means, said memory means being mounted in said memory module and being permanently coupled to said sensor means, a multi-conductor lead connected between said sensor assembly and said memory module, and connecting means in said module connected to said lead and to said memory means.

68. The unit of claim 67 combined with a flow cell and wherein said sensor assembly is mounted in said flow cell.

69. The unit of claim 67 wherein said connector means includes a connector housing and connector pins mounted therein with said memory means for facilitating coupling of said sensor and memory unit to a signal processing and conditioning circuit, said memory means being connected to said connector pins and said lead being connected between said sensor means and said connector pins.

70. A sensor and memory unit consisting of sensor means that provide an electrically processable output signal, directly and electronically readable non-volatile memory means for recording the information data relative to the particular sensor means for use in setting up information processing means for processing signals from said sensor means, such as offset data, amplification data, etc., and for supplying said information data to the information processing means so that when such information processing means are coupled to said sensor and memory unit and energized, the information data immediately will be received by processing circuitry within said information processing means which is then set up so that said information processing means can treat the combination of said sensor means and said memory means as an ideal sensor and provide an output signal, relative to a signal generated by said sensor means, equivalent to the output signal which would be obtained from perfect sensor means, means for permanently connecting said memory means to said sensor means, and means for connecting said sensor means to signal processing means for processing signals from said sensor and memory unit, said memory means being carried by said connecting means.

71. The unit of claim 54 including a memory module which has said memory means therein and which is connected to the proximal end of said catheter, and connector means mounted in said memory module for connecting said memory means and said sensor means to signal processing means.

72. A sensor system comprising: a sensor assembly consisting of sensor means capable of providing an electrically processable output signal and memory means associated with said sensor means and containing information data for use in setting up information processing means for processing signals from said sensor means, such as offset data, amplification data, etc., relative to said sensor means; means connected to said sensor means for processing the sensor output signal to obtain a sensor system output signal and for reading out said information data from said memory means, said memory means including a non-volatile memory having the information data relative to said sensor means recorded therein and being permanently coupled to said sensor means, and said processing means comprising signal processing and conditioning circuitry capable of taking output signals from said sensor means and processing them through at least a first signal path in said signal processing and conditioning circuitry, and of taking said information data from said memory means and processing such information data through a second signal path having means for detecting and processing said information data recorded in said memory means and means for influencing the processing function of the signals from said sensor means via said first signal path in dependence upon the information data recorded in said memory means.

73. The sensor system according to claim 72 wherein said signal processing and conditioning circuitry includes and utilizes a microprocessor for the detection and processing of said information data recorded in said memory means in order to influence the transmission function via the first signal path and in dependence upon the information data retrieved from said memory means for processing and conditioning said sensor output signals and for supplying the conditioned sensor signals to an output terminal.

74. The sensor system according to claim 60 wherein said sensor means is mounted in a distal end of a catheter.