Modbus communication with Alstom relays

  • Thread starter Fernando Capelari - Schneider Brasil
  • Start date
F

Thread Starter

Fernando Capelari - Schneider Brasil

We have a customer that is using a M1E CPU 98030 to a read the variables of some Alstom relays. The part numbers of the different relays are:

P343311B2A0030A,
P141311A2A0050A,
P143311A2A0050A,
P122A00F111,
M220

The customer said that if he tries to read more than 28 registers, the XMIT block goes to error. We don't know the reason, because XMIT can read more than 100 registers per transaction, using the Modbus function code 3.

We have a customer that is using a M1E CPU 98030 to a read the variables of some Alstom relays. The part numbers of the different relays are:

P343311B2A0030A,
P141311A2A0050A,
P143311A2A0050A,
P122A00F111,
M220

The customer said that if he tries to read more than 28 registers, the XMIT block goes to error. We don't know the reason, because XMIT can read more than 100 registers per transaction, using the Modbus function code 3.

Has anyone ever worked with this relays and can give a suggestion?
 
Your must ask to your customer what register they try to read and what response code that the MiCOM relay send back, in order to determine what actually happen.

Depend of the answer there exist many thinks that could be happen. One maybe that they try to get a not available register.

You must have in mind also some information in the relay (disturbance records) are stores in compressed format and for that this information must be read using a paging system.

I do not know the CPU that your customer use and how the XMIT function block works but i hope that this little information can help you.

Luis Rios
 
I have had the same problem with a older device that did not allow more than 18 Modbus registers to be read. I had to make several XMITs to
get all my data. You also could be asking for data not avaliable.

good luck
 
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