How to read input coil status with BMX NOM0200 (RS485) by READ_VAR

[Himanshusingh3]

Hi,

         We are going to integrate third party equipment on Modbus RS485 through  BMX NOM0200 in M580 system, we are able to scan all Holding register, input register but how to read/scan input coil status by using READ_VAR function block????

[RoozeeR · Accepted solution]

Hello,

The READ_VAR function is able to Holding register (%MW), Input register (%IW) and Inputs (%I or 1xxxxx references) and Coils (%M or 0xxxxx references): See READ_VAR help in Control Expert, regarding the object type input on the READ_VAR function:

Type of objects to read for Modicon M340 and M580 CPU:

• ’%M’: internal bits
• ’%MW’: internal words
• ’%I’: input bits
• ’%IW’: input words

[Himanshusingh3]

Thanks for input, @RoozeeR 

I have one more question how we can reset slave devices which gone in Request time out mode by auto as per preset time, because in application devices will not be online all the time only will be online when ever in duty mode.

[RoozeeR]

Please explain what do you mean by "how we can reset slave devices which gone in Request time out mode by auto as per preset time":

- Do you need to reset the device itself, or reset the READ_VAR function becuase of the timeout?

[Himanshusingh3]

@RoozeeR  not slave devices we want to reset READ_VAR FB which gone in Request time out

[RoozeeR]

You have to set the request timeout value in the Communication Management Parameter (Gest Input):

Please note the value given is *100 mS (10 = 1 second). Make sure the timeout value is longer than the  reaction time of the device.

With Timeout, the Function will exit with request timeout and ready for a new command.

If you set the Timeout = 0, the timeout time is infinite, so the function will not exit: Do not use a 0 value.

If this happens you can use the CANCEL function to reset .

[Filipe_Brito]

Good Morning;

if I have a very large timeout, can this be a problem? I have 65 blocks of read_var and a timeout = 1000 and I am not able to read all the blocks.

[chrism1]

Did you ever fix your problem. I am currently reading 50 blocks of read_var and a timeout of 500 and i am not able to read all the blocks. Does increasing the timeout help?

[MatthewM]

I think this should be a new thread.  What do you mean by "50 blocks".  Do you mean you have 50 READ_VAR instances, or 1 READ_VAR with 1 read of 50 words, or 1 READ_VAR with 50 reads of x number of words?