1. NST is not as fault or error. It is a status of drive like, ACC, DCC, RUN etc...(NST means, the drive is in free wheel stop mode)
2. Most of the cases, it can happen due to any of loose connection or wiring disconnection in Logic input wiring (LI1 or LI2 etc..)
3. It can also happen due to failure of power board. Please check the +24VDC is available in Drive terminal. If the +24VDC is missing in drive terminal, it can also show "NST"

Suggestions:
1. Check whether the 24VDC is available in drive terminal or not.
2. If 24V is not available at drive terminal, please arrange to replace the power board and control bard.
2. If 24V is available, in 3 wire configuration, locally short(with a small wire) the +24V terminal and LI1 terminal and check the drive is showing RDY.
3. If 24V is available, in 2 wire configuration the drive should show RDY with out any of connection.
4. If the drive is showing RDY, you can give run command (LI1 in 2wire or LI2 in 3 wire configuration) and check the drive is working.

5. If the drive is not working after above checking, Please check the drive operation from HMI whether it is working or not. Even If it not working in HMI, you may arrange to replace the drive power board and control board

Released for:Schneider Electric Egypt and North East Africa