Hi everyone !

I have a CPU S7-1200 ( CB1241 ) and 2 inverter ( ATV12 - schneider )

how to communicate between a CPU and 2 inverter  with modbus RTU ?

When Master  read/write data on inverter .  if it's not continuous infusion , the inverter will error .

That is error : "

Hello,

so this is simple message that you don't execute from PLC message to defined timeout. What is set on inverter? Only think due that message from inverter.

xGolem

Hi everyone !

I have a CPU S7-1200 ( CB1241 ) and 2 inverter ( ATV12 - schneider )

how to communicate between a CPU and 2 inverter  with modbus RTU ?

When Master  read/write data on inverter .  if it's not continuous infusion , the inverter will error .

That is error : "

Modbus time out : 0.1 to 30 s The drive detects a Modbus fault if it does not receive any Modbus request at its address within a predefined time period (time out)

So If I change modbus address , the inverter will stop and error ! 

The default for such drives are to go into an error state if they do not receive any communication from the master for a time-out period.

Some drives can be set to make a warning or ignore such a case... you need to read the drive documentation to see what you have available.

You can set up a schedule on your PLC to link regularly to each drive. Even if just requesting the current speed, will be enough to refresh the time-out.

Have a look at one example made for the Siemens drive..
https://support.industry.siemens.com/cs/ww/en/view/63696870

This idea (frame not the Modbus addresses) will also work for you.

Helpful?
w