Hi Pegaia,

I have a CPU 1214C DC/DC/DC which is connected to MMPS module (for measuing, diagnosing and controlling the sensor vibration of mine fans). To be honest, I am a beginner user for PLC. I am trying to find signals on PLC program which are used on module. Generally could you give me some concepts about how to establish a connection PLC with module's signals(I/O)? 

Denilson Pegaia

edsel lin

Thanks Pegaia,

How about the digital, is it need another DB?

And about the write or read command, is it all controlled by the client only?

How to program the write / read command? I can only do it one way (read or write) cannot do both.

Hi,

Modbus with S7-1200 has binary access just to inputs (Ix.y) / outputs (Qx.y).
If you need to get some binary information on DB, either your alloc a register (word) to the signal or group several signals (16) in a register.

About the read/write, you can control de access (all), by disconnect port. However if you enable to write, doesn't make sense to limit the read. In other way, if you doesn't want that the cliet writes, it just a questio to doesn't do anything with the interface DB on the client.

Your are write, either you read or your write. Both simultaneaus is not possible.

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Split from Tips and sample program for MODBUS TCP.

Hi,

create two DB's one for read, one for write then configure two Modbus blocks also one for read (mode 0) and one for write (mode 1)

Then read your DB's into your PLC program.

Regards