Single device to Mulitple Controllers

I'm looking to take a single device like a RTD temperature sensor, 4-20mA pressure transducer or 0-10V damper feedback to multiple controllers. Can I do this? With some devices, but not others? What are the limits and is there anything I really need to watch out for?

Thanks in Advance,
Baxter

hi search google for mA splitter

Can you pass the input from your temp sensor to the other controllers via messaging?
Are your controllers linked in any way? (i.e. ethernet, DH+, profibus, etc)

It would help if you posted what processor you are talking about (Seimens, GE, A-B). A-B supports messaging between controllers. You can also add the analog module from another processor directly into your tree. You could also use a splitter. Now if you are talking about Seimens I wouldn't know but others here would.

1) RTD can go to one device only. No exceptions.

2) Sometimes it works to go to more than one device, depending on common mode and ground loops. It's a try-it-and-see situation. If it works, fine. If there's an offset or the signal drives 'off-scale', then you need isolators or isolated splitters.

3) 4-20mA is a current signal. It runs in series from one device to another. Combined resistance must be lower than the max resistance spec of the device.

4) 0-10Vdc signal is a voltage signal. It runs in parallel from one device to another. Minor error due to parallel resistances.

5) If you connect an RTD to a temperature transmitter, you now have a current or voltage signal that might go to more than one device.

6) The recommendation for an analog splitter (presumably isolated outputs) is a proven solution.

7) Digital comm between controllers works, too.

The bad thing about passing a signal via message or series wiring is if the power drops out on the first PLC it can change your signal scaling or it may also drop out the signal, if you are doing any controlling this could be bad..

A re-transmitter or signal splitter is the best way