FP-AI-110 won't see my externally powered current source

[puppet]

I have wired an Omegadyne PX5800C1-0O15G1 pressure transducer, I think according to your instructions. I am getting no sibnak at all. I've attached diagrams showing my circuit and the one called for in the FP-AI-110.

Help?

[Aaron_G]

Puppet,

I was on Omegadyne's website but was unable to locate specs on the PX5800C1 model. I did locate the following information that may assist you in wiring the system properly. The following page lists the common wiring techniques for different Omegadyne sensors:
http://www.omegadyne.com/press-trans.html . In particular Figure 3 shows the proper wiring for the 4-20 mA sensors. When you compare Figure 3 with your attached diagram, there are a number of discrepancies. First of all, the Vsup terminal of the FieldPoint module should be connected to the Sensor+ line and the Sensor- line should be connected to the IinX terminal of the module. In your drawing, the sensor appears to be wired backwards with respect to the Omegadyne sensor.

Also, may I ask wh
y you are including the extra resistors and the zener diode? With the polarity the zener diode is currently wired in, the current flow from the power supply will be biasing the zener to the on position, shunting power flow away from the sensor and directly through the Iin terminal of the module. With a 15 VDC power supply, and a 0.7 VDC drop in the zener, this will result in up to 83 mA of current flow through the Iin terminal. This is calculated with a 14.3 VDC source (15 - 0.7) across the 173 Ohms of input resistance (100 Ohms for the FP-AI-110 and 73 Ohm in-line resistor). IMPORTANT: This current level is more than the module is rated for (30 mA) and will have damaged the input channel on this module.

Regards,
Aaron