Dear all,

I need a help regarding this modbus rtu communication. i had four generators with modbus rs485 connected in multidrop setup. 

we had an CMTP module added to PLC module ET 200 SP. 

My problem is during starting am getting communication with all the generators, but when i do a power cycle i am losing communication, what will be the possible reason for the same. is it because of program or i need to enable something. 

what i had done is i had enabled a counter and whenever the the counter value changes from 1 to 4 . i am enabling one modbus_comm_load and modbus_master_db. isnt what i had done is correct or wrong.

Is there any troubleshooting techniques to check the same

is there any project sample with communication to 4 slaves..

Thanks and regards

Antony

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Split from modbus and modbus RTU library.

where do you do the power cycle? on which device?

I think it is normal, when there is a power-cycle at one of the communication-partners that the communication needs to be established again.

regards,

Dear sir,

Power cycle mean i am doing power off/on for the PLC. when i do the same PLC loses communication with the slave modules. At that time Tx is blinking at the same Rx does not have any indication.

thanks and regard

Antony