Modicon Compact ADU211 Card


Thread Starter

Eric Allen

Has anyone had luck with configuring a ADU211 Analog input card on A a E984-275 Compact controller using either the ladder logic or a FBD that of course does not exist. While I'm on the subject. Has anyone had any luck with the XXmit
block for reading Modbus slaves?


I have used the XXmit and had success. I used 9600 baud, 8E1 and set the 8th bit in the command word (Modbus Messaging) If you are using a radio modem you will most likely need to set bit two in the command word as well for RTS/CTS with the radio Modem. One thing I noticed was that the response timeout had to be set to at least 150ms in my particular application in order to assure good responses without retries. Anything less, in my particular case, caused an error.

Michael J. Maliga

I have had a lot of luck with the ADU211.
The program in the I/O book works OK.
I have generally created a timing routine (either in Proworx or Modsoft) that runs it a bit more
orderly. I see that this is not new, so if you are interested in it, drop me a line at
[email protected].
The real trick here that helps is to use coils to do the configuration, and segregate them in the
networks by function. Then just BLKM the coils into the control registers.
I have tried to get my hands on the software to write the Function Block, but it seems not to be
Just one note - the card works OK on temperature applications, but is just too deathly slow for
pressure. I have had to put other hardware in their place to operate in pressure loops.
The temperature problem that I have faced is that RTD's only let you have 2 inputs. Otherwise,
they are superb for thermocouples(oh - make sure that they are ISOLATED thermocouples).
I have over a dozen of these in service in various applications.
Mike Maliga