I have a question about wiring in the above-mentioned sensor to this PCB. First, I was hoping the board itself would power the sensor, but it appears that this isn’t the case. sigh
So following your diagram for a 2-wire sensor, you show a ‘Signal’ wire going to the positive terminal of the PCB, and the other wire going to the positive terminal of the external supply, and the negative terminal of the supply connected to the negative terminal on the PCB (for each channel). Omega’s datasheet/manual has the pins on the sensors labeled as such:
Pin 1: Supply +
Pin 2: Supply -
Assuming Pin 1 of the sensor is the ‘signal’ wire and goes to the positive terminal on the PCB and Pin 2 goes through the supply, I’m measuring -12V on the PCB terminal for the sensor channel when putting my negative meter lead on the negative terminal, and positive meter lead on the positive terminal. Is this right, or should I reverse the wiring?
Also, any chance of a rev update to the board so it supplies the power to the sensor directly? I feel like this would simplify things greatly for the end-user. Thanks!
Sorry the engineer who generally provides support for our 4-20mA products is out of town this week.
Are you referencing this diagram?
If so it seems like you would not get a negative reading on the +/- terminals on the board. That said I am far from an expert on 4-20mA signals. Also we do have some devices which I believe power the sensor. These are Current Loop Receivers, you can take a look at a few here:
No worries, I get it - just thought the unusual lack of response was, well…unusual. The boards that supply power only supply 5V, the sensors I’m using need a minimum of 8V to operate, so the other boards in your catalog won’t work. I’d still love to hear from the other engineer when they get back just to make sure things are clear before powering the sensor up. In the meantime, I have some questions about the code, which I’ll start a new thread for. Thanks!
we have a different product which is designed for 2 wire device and it provides loop power.
Well, shoot… That’s pretty much what I wanted in the first place. I may order it, but I think I can get the current board to work if I sort out the wiring. The external supply source isn’t a big issue, just a little extra wiring.
As far as wiring the sensors to the current PCB, I’d still like some clarification please (see initial post for details).
in the 4-20mA wiring the goal is to complete a loop. the wiring diagram travis shared is correct.
one wire from sensor will directly go into board and one will have battery/power in series.
Right, but in Omega’s documentation, the pins are labeled ‘Supply +’ and ‘Supply -’ on the sensor, nothing about one wire being ‘Signal’ like in your diagram. Your diagram shows one wire going to the positive terminal of a power source, and the other (labeled Signal) going to the positive terminal for the designated channel on the PCB.
checkout the first diagram.
connect supply + to power +