Powerflex not stopping motor

Hi all,

I have a Powerflex 40 controlled by a 1769-L24ER, when VFD parameter P036 is 0, motor starts and stops normal but when parameter is changed to 2 to run in auto with system, motor will not stop when VFD is at 0Hz.

PLC and HMI show motor as off, but keeps running.

Any suggestions? Any help will be much appreciated.

Setting P036 to 2 makes stop = coast. You might look at P036 = 1 which allows you to set P037 to a different stop mode like 0 ramp clearfault.

Its a powerflex 40 where
P036 [Start Source] = 2 “2-Wire” I/O Terminal 1 “Stop” = coast to stop.

check what speed is being selected by P038 [Speed Reference]
Check what speed reference speed is coming from either the pot wheel or selected by dig inputs.

since your selecting input 2 dig input on by 2 wire, it will select what speed is in A052
06 Digital Input 2 Preset Freq Program with A052 [Digital In2 Sel]. A052
A052 [Digital In2 Sel]

As you can see selecting 1 dig input does other things. Kind of confusing at first but once you get used to it just does what your telling it to do.

I like how they repeat so many times in the manual that start source 2 = coast to stop yet when they show the wiring example you get this...

Right now the drive is set as

P37 0
P38 4
A52 4

Is it better to set P37 to coast to stop instead of ramp to stop?

0 “Ramp, CF”
1 “Coast, CF”
4 “Ramp” Ramp to Stop.
5 “Coast” Coast to Stop.

mmbte said:

Right now the drive is set as

P37 0
P38 4
A52 4

Is it better to set P37 to coast to stop instead of ramp to stop?

0 “Ramp, CF”
1 “Coast, CF”
4 “Ramp” Ramp to Stop.
5 “Coast” Coast to Stop.

Click to expand...

Depends upon your application. Ramp to stop will force the motor to stop rotating upon receiving a stop command. If you're driving a high inertia load, you can prevent excessive regeneration feedback to your drive by allowing the motor to coast to a stop.

In some applications it may be that your motor will stop quickly even in coast to stop mode without the need to use the ramp to stop option.

Is it controlled via IO or Comms?