keller 23 pressure sensor

Determine how to drive and read an unknown three wire pressure sensor

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This three-wire pressure transducer pinout, drive type, and electrical specifications are unknown. It should be a typical industrial transducer. I have tried assuming it is an amplified device with a 0-5, 0-10 V output, or 4-20 mA output. No combination of wiring results in a correlated output signal.

The transducer comes out of a late 1990’s designed Agilent 1100 HPLC scientific pump, where it measures the output pressure up to 440 bar (6500 PSI). It is part of a pulse dampener, so I wish to keep it intact. I do not have access to the drive PCB any longer.

The markings are: Agilent Technologies Part No. 5065-9907 Revision A Date code 21/03 PA-23R / 81088 440 bar

I suspect this may be a Keller OEM transducer. Keller’s currently advertised lines do not include a 23R, but they follow a similar product naming convention – PA-23R could make sense.

The transducer has three wires in a 0.100 pitch ribbon cable, so unshielded, One is black striped.

I’ve monitored the drive voltage while powering the transducer for repetitive pulses as evidence of a microcontroller.

The only configuration that shows any response at all is #5 below. The output voltage decreases slightly as pressure increases. However, the output voltage depends on the supply voltage. This seems unusual if it is an amplified transducer.

The pin-to-pin resistance matrix is:

pin 1pin 2pin 3
pin 1x1.52 MΩ13.98 MΩ
pin 21.52 MΩx11.12 MΩ
pin 313.94 MΩ11.08 MΩx

The pin-to-pin voltage drop is:

pin 1pin 2pin 3
pin 1x1.64* Vopen
pin 20.73 Vxopen
pin 31.93 V*1.72 Vx

*Values decreased when attaching the meter.

Powering the transducer with a 15 VDC supply current limited to 60 mA gives this result set:

Configpin 1pin 2pin 3current (mA)
1+150out43 mA
2+15out016 mA
30+15out22 mA
40out+150 mA
5out+1500 mA
6out0+150 mA




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1 Answer




Keller 23 Connection

Keller 23


(1) Keller 23 Datasheet

(2) Keller 23 Connection



answered 3 mins ago


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