S7 1200 SM Module configuration

Dear Friends !

I am using siemens analog input module 6ES7231-4HD32-0XB0 for S71200 PLC, to connect with 2 wire configured transmitter. When I check the analog channels I don't get 24VDC, and my transmitter is not work.

Is the module doesn't support 2 wire system? shall I need 4 wire system ? or my wiring is wrong?

Here is I attached my wiring diagram and siemens corresponding manual.

Thanks,

Senthilkumar.K

...When I check the analog channels I don't get 24VDC, and my transmitter is not work.

...

The Analog Inputs in 2-wire Connection will NEVER give you 24V!

They will give you max. 10V and not even that.

If your Transmitter really needs 24V, it seems to be a 3 or 4 wire Transmitter...

Check the manual of AI board,  if 2 wire is possible at all.

Check the manual or data sheet of the transducer.  A 2-wire system needs the sensor power to be provided separately.  If the sensor is loop powered, meaning power from the input device, then a 4-wire system is needed.  Without that information, then no one can help you.

Jeff Casagrande

... A 2-wire system needs the sensor power to be provided separately.  If the sensor is loop powered, meaning power from the input device, then a 4-wire system is needed.  Without that information, then no one can help you.

No, that is wrong!

3 or 4 wire: power supply separate.

2 wire: power supply from analog Connection. Mostly Transmitter 4..20mA.

 Not entirely .  But one needs to look at the device datasheet to see what is required.  Analog inputs are analog inputs.  They get a voltage or current and convert them to digital.  The device needs to provide the input.

IBN-Service

No, that is wrong!

Hi all,

I have the exact same problem, and from all the hits this posts has received, I believe many more are having this problem, and missing some vital information to power 2 wire - loop powered intruments with the 231-4HD32-0XB0 , 4 channel analog input card.

With a S7-300 331-7KF02-0AB0 analog input card, from the 2 or 4 or 8 channel version, all of them when configured allows for 22-24 VDC to be present at the terminals of a channel on the A+ terminal. With the 1200 4HD32 card, this is not the case, there is no voltage present. To test if the input card reads a 4 wire instrument, the test proved positive and I got my analog reading from a loop tester.

So my tests shows that 4 wire can be read with 1200 card, but not 2 wire.

Please clarify if the 1200 analog input card can power a (2 wire) loop powered intrument, or must I install an S7-300, or change my instruments to 4 wire to work with 1200 analog cards.

a friend of mine just managed to solve this un-answered question for me.. 

Attachment shows how to wire loop powered (2 wire) instrument on the 6ES7 231-4HD32-0XB0  card.