Dear Experts,

i want to communicate im151-8 pn/dp as a modbus(RS 485 RTU) slave.

I am using cpu and 1SI Module 6ES7 138-4DF11-0AB0, it is configured as mosbus slave

i am Using software STEP 7 Professional V12

for testing I am using Modbus tester as a master, when i send query from modbus tester, RX led gets on, but in program, S_MODB gives error info as 16#0811

i am not getting its meaning in any manual. please help, how to resolve.

Thanks in advance.

Damayanti

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Split from RS485 Modbuss.

Dear Sir,

thank you for your support.

CP START signal was not pulse but a continuous on signal, i made it as pulse signal, now there is no any error.

I am using modbus tester as modbus master, when I send query from it, RX led lits, but at modbus tester end i am getting "TIME OUT" Error and no any data is received

to read flags say M0.0 to m0.7, which data type to be used and what will be starting address?

in conversion DB, START address for flag is "0"

i am using  Software STEP7 PROFESSIONAL TIA V12

I have attached my program copy.

please help.

Thank you.

Damayanti

Hey,

Its done in simatic manager.

Will try with TIA tomorrow..

Thank you all.

Damayanti