hi expert 

I have a CPU S7-315, communicated via Profibus with six drives three of them Danfoss and the rest three are Sinamics G120C 

the Sinamics drives a three fans in the sterilization Tunnel of critical area which mean no way to turn off any of these fans.

the problem is duo to any losses of communication the sinamics drives stop. 

so I am looking for any configuration/parameters of the sinamics drives to let the drive run even if the communication is interrupted as a reference operation, if  no connection the drive run with base speed .

i hope to find a solution for this issue.

thank you in advance Expert.  

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Split from Ask Expert for help.

Hello,

you can use one CDS for control from PLC, second with fixed speed. Than you can switch between them (p810) using r2043.0 bit, which indicate setpoint failure.

And because of state of this bit, you have to define 1st CDS for fixed setpoint and 2nd for PLC or if you want 1st one for communication, you have to invert state of this using NOT block (p20078 - p20080).

Next thing, you have to change setpoint fault into no message or warning using parameters p2118 (message number ) and p2119 (message type) to keep drive running.

With regards

Martin