Why does the ATV31 or ATV312 show a code of nSt even though there are no assignments in any of the parameters for a freewheel stop activation?
Altivar ATV31 and ATV312
The drive status is showing NST on the main display and it will not clear. The drive will not run
Here are a few possible causes:
(A) If a directional run command (forward or reverse) is present on power up of the drive and the drive is set for 2C (2-wire) with [trn] transition control or 3C (3-wire) control with the LI1 NC stop being open, the drive will show nSt indicating that it will not run.
- 2 Wire control solution: Try setting the two wire type parameter tCt to Level control (LEL) menu in the IO menu.
- 3 Wire control solution: Make sure that LI1 the stop NC input is turned on when the drive is powered up. If this input is open the drive will display NST until you close this input.
(B) Check to see if someone has pushed the stop button on the local control or the remote HMI while the drive is being commanded in the terminal mode with starting and stopping via the logic inputs.
Solution: power cycle the drive to see if the NST clears
(C) If the reference channel or the control channel is assigned to Modbus or CANopen, the drive controller displays nSt on power up and remains stopped until the communication bus sends a command.
Solution: If the drive is programmed for NET control, you will need to write a Hex 6, then Hex 7 then Hex F to get the drive to start.
(D) Check to see if you have a logic input assigned to a freewheel stop in the FUN menu StC parameter then NST parameter.
Solution: Turn on your logic input that is assigned to freewheel stop. Otherwise, the drive will stay in NST mode until you turn on the assigned logic input.
To make adjustments to the drive parameters, see the Altivar 31 or Altivar 312 Programming manuals.
ATV31 Programming Manual:
ATV312 Programming Manual: