2 wire and 4 wire transmitters on the same STBACI1400 module?

[Gilly]

Hi, 

a customer brought up this rather simple question but i would like to confirm if there would be any interference in signal if we wire let's say a 2 wire transmitter on channel 1 and a 4 wire transmitter on channel 2. They would have to share the same return on pin 3. 

Below are the schematics for 2 wire and another for 4 wire. But we do not have documented anywhere a mix of both. Appreciate the help! Thanks

[JerryBartlemay]

Hi Gilly,  the answer has to be "it depends".  The four wire transmitter is externally powered.  If its power source is electrically isolated from the signal, then it should be okay.  If, however, the transmitter shares commons between power and signal, or if they are referenced to ground, that spells trouble.  To be safe, I would use a signal isolator in the four wire transmitter circuit to ensure isolation.