A NST message appears during the operations

[Vince83]

Hello,
I'm working on ATV320 with an Ethercat Interface board with CHCF set on I-O. When RDY message is displayed I send a controlword with a Forward or Backward command and the inverter starts. StatusWord become UINT#1591. After a while StatusWord changes to UINT#1616, a NST message appear on the display and Inverter stops with statusword UINT#592.

What's going on? Why it doesn't continues to run ?

Thanks to who'll help me!

[Ahmed_Alzafer]

NST is a very general status on drives.  It is not a fault condition.

See below for a number of reasons why NST is present depending on application/setup.
Causes and fixes :
 

The drive is in 2 wire control (TCC = 2C) and was powered up with an active run command.
Cycle the run command or set TCT to LEL. (IO menu, 2 wire type = level)
https://www.se.com/ww/en/faqs/FA238669/

The drive has an input assigned to Freewheel stop, NST.
The input needs to be active.
https://www.se.com/ww/en/faqs/FA170907/

The drive is in 3 wire control (TCC =3C).
LI1 must be active before the NST will clear.
https://www.se.com/us/en/faqs/FA274804/

The drive is being controlled by serial communication, and drive is not receiving the proper command signal.
The drive will display NST until the correct value has been written to the command word.
https://www.se.com/ww/en/faqs/FA314997/

A loss of a 4-20mA signal is programmed to freewheel stop.
When the input is lost, status goes to NST. Verify the 4-20 mA signal.

The drive is in terminal control, and the STOP button on the integral or remote keypad was pressed.
While in terminal control, the STOP button functions as an E-STOP.  If the keypad STOP button is pressed, the drive will go to NST (excluding the ATV212, which will display a flashing "E"). Power cycle the drive to clear the NST.
https://www.se.com/us/en/faqs/FA164112/

For the ATV61/71 VFD only: If the drive is running, and the voltage applied to the PWR input terminal drops below +19Vdc, the drive will stop and display NST.
You will need to make sure you close the +24 VDC to PWR input and cycle off and on the run command again. Make sure the factory-installed jumper between +24 and PWR is connected firmly. Or if a safety circuit is connected to these terminals, be sure the circuit is closed.  

https://www.youtube.com/watch?v=pA2F0-2ilIM&t=1s

[Vince83]

Thanks for your Replay @Ahmed_Alzafer !

I already read a lot of documentation and FAQs, included which ones you suggested.

All the cases you reported don't include this case unfortunately. 

TCC = 2C -> NO

TCC= 3C -> NO

NST is assigned to DI -> NO

Drive is not receiving the proper command signal -> For sure it gets the reset, forward and backward command, if Communication falls could be showed an error?

A loss of a 4-20mA signal is programmed to freewheel stop -> NO

The drive is in terminal control, and the STOP button on the integral or remote keypad was pressed -> NO and I think there is not an STOP button on ATV320 (there is ESC button and small knob to browse the menu).

Any other ideas? How I can see the root of NST message?

[RaviNayak]

Status Word changing from UINT 1591 to UNIT 1616 and then UINT 592 show the Bit 5 of the status word is changed from 1=> 0.

This means the Quick Stop is active in the drive after the drive reached the desired reference.

The drive performs a fast stop and remains locked in the operating state 6-Quick stop active.

Before restarting the motor, it is required to go to the operating state 2-switch on disabled.
During fast stop, the drive is unlocked and power is supplied to the motor.
The configuration parameters cannot be modified.

The condition for transition 12 to state 2 - Switch on disabled depends on the value of the
parameter Quick stop mode (QStd):

• If the Quick stop mode parameter has the value FST2, the drive stops according to the fast
stop ramp and then changes to state 2 - Switch on disabled .

• If the Quick stop mode parameter has the value FST6, the drive stops according to the fast
stop ramp and then remains in state 6 - Quick stop active until:

◦ A Disable voltage command is received or
◦ The STOP key is pressed or
◦ A freewheel stop command via the digital input of the terminal.