What would cause the ATV312 drive to run at a fixed speed of 15hz and not follow the analog input signal?


29 July 2022

ATV312 running at 15hz and not following analog input signal.

Product Line:
Altivar ATV31 and ATV312


The drive is not following the 4-20mA input signal and always runs at 15hz.


The VFD may be running at the low speed LSP = 15. 
Verify that the 4-20mA signal has positive voltage on AI3.
Verify that the VFD reference source is set to AI3.  Reference switching or forced local could be changing the source from AI3.

The VFD may be running at a preset speed setting.
Check the Preset speed function in the FUn menu, PSS submenu, parameters PS2 and PS4.
If the preset speeds are programmed, verify that the logic inputs are not active.