4-20mA XMITTIER INTO 2 INPUTS?
4-20mA XMITTIER INTO 2 INPUTS?
(OP)
i need to feed a signal from a single pressure transmitter into 2 inputs on an allen bradley plc.
can this be done?
if so, how?
thanks for any suggestions.
can this be done?
if so, how?
thanks for any suggestions.





RE: 4-20mA XMITTIER INTO 2 INPUTS?
-----------------------> 4-20 mA
+ -------RCVR1--------RCVR2------- -
The 4-20 mA loop was once designed for just this, connecting several devices in series. In the older days (when all devices were moving coil type recorders and indicators) the insulation came naturally. Today, one has to look carefully to find true floating circuits, but I am convinced that AB has them.
Just connect and watch it work! You can not destroy anything, really.
RE: 4-20mA XMITTIER INTO 2 INPUTS?
But a PLC program change might make sense instead. Just a thought.
RE: 4-20mA XMITTIER INTO 2 INPUTS?
if you have isolated 4-20mA inputs series them, otherwise bring your ma signal to a common sense resistor and monitor the voltage with your two inputs.
Some input cards allow universal (mA/vdc) monitoring.
RE: 4-20mA XMITTIER INTO 2 INPUTS?
a software change is definetly the prefered solution but no one here is willing to buy the required software(anyone know of a lower cost program to access allen bradley controllers).
i found a work around by changing the order of the inputs which exploits a software quirk.
thanks for all your help!
RE: 4-20mA XMITTIER INTO 2 INPUTS?
some mA input cards are actually voltage inputs with a sense resitor in place. what has the A/B supplier advised?
RE: 4-20mA XMITTIER INTO 2 INPUTS?
But maybe I'm the one that's confused. Can David45 or anyone illuminate this for me?
RE: 4-20mA XMITTIER INTO 2 INPUTS?
a common for the entire input card is tied to the power supply ground.
the allen bradlety appears to let you set up 16 inputs/card this way or 8 inputs/card if you need isolated grounds.