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Can two ATV212 drives receive a speed reference from one controller at the same time?

FA240841

28 September 2021

Issue:
Speed reference from one controller to two ATV212 drives.

Product Line:
Altivar 212 and Altivar 21

Environment:
All models and serial numbers

Cause:
None

Resolution:
Yes, depending on the controller signal capacity.  The drive analog inputs could load down the signal from the controller.  The VFD impedance on the current input (VIA) is 250 ohms.  The impedance on the voltage input (VIA and VIB) is 30k ohms.  If the controller output cannot maintain the signal, then consider applying the reference signal to one VFD and then using the analog output of the first drive to feed the analog input of the second drive.