I have six Omega sensors. Two flow meters which output a 0-5v signal, and four pressure sensors which output a 4-20ma current.
The Omega units rely on 13-36v excitation. I'm using two channels of a SCXI-1124 module to produce 20v.
The readings coming back from the sensors are being handled by a SCXI-1102 and SCXI-1303 terminal block. On this block I have 10megohm resistor networks on the bias and pull-up for each channel being used. The channels that are being used for current also have a 249 ohm precision resistor bridged across the + and - terminals. The - terminal for all these channels are all tied together and connected to the ground terminal of the SCXI-1124 channel being used, per Omega's manual which states "If the power source (in my case the 1124) does not originate from the receiving device (the 1102/1303), the negative side of the power supply must be connected to the signal ground of the receiving device".
The wiring diagram of the 4-20ma shows power in to the + side, signal out of the - side, and an earth ground. I've connected the earth ground wire to my chassis ground terminals on the SCXI-1124/1325 and 1303/1102. The - signal terminals on the 1303 channels are all tied to the 1124 power supply ground, completing the circuit.
I'm not sure if anyone can make heads or tails of that, but do I seem to have the grounding correct? I know in my previous questions, grounding and ground referencing have been mentioned quite a bit. I followed the sensor instructions as closely as possible and referred to all information imparted to me on here. I'd just like a second opinion before hitting the 'go' button and perhaps hurting something.
Any and all input is appreciated.
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Still confused after 8 years.
