Hi friends! Need some advice on AC500 Modbus communication..
working on Modbus serial communication using MOD_COM_Mast. I have AC500 plc that needs to talk to three third party drives. I have to write& read from 1797,1798 ( drives Modbus address for speed ref and cw resp. for all three drives) and also only read from modbus address 2049(drive modbus address for speed feedback from three drives). I can read and write on 1797 and 1798 but can't read from 2049. I have attached the program for your reference.
I tried to consolidate three modbus address in single MOD_Com_Mast but the number of words that it can read is over the limitation, fc 3 can only do 125 words. I created a separate MOD_COM_Mast for modbus address 2049 but it overwrites in two of the first modbus address (1797,1798) and also when i am online it doesn't respond at all.
(1797-2049 is 253 words)
How do i resolve this issue.. need your help please.
Everybody's enjoying thanksgiving, but i am here trying to figure out this problem.
Please have a look at the program and let me know what i am missing..
I would be so grateful.
Thanks
Answers
Yes bbel is correct ....
You just remove all read function and try to write first into one address of drive...
Consider task time atleast 300 ms initially after you can decide upon communication response.
by MTHOBISI Rank: 1537 on 1/20/2016 11:44:15 PM | Like (0) | Report
I'm writing a software for Interfacing a PLC with an M2M Network Analyser. I'm using the ETH_MOD_MAST function block. can you please assist me with configuration setting on Control builder plus, and the values that I need to put on the function block: slot ? unit_id ? fct ? addr? NB ? and Data. I can be happy if you you can suggest something that can make me achieve what I want to achieve. I want to be able read the measured values from the ABB M2M network ANAYSER.
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