ACS800 start with reverse direction everytime

[qinyong97]

Hi, I have issue with acs800 starting the motor in reverse for like 5-6 seconds with a max speed of around -220 rpm before it goes to the requested direction which is forward. What is causing this?

 

[BryanG]

If it isn't freewheeling, then it is likely following the instructions it is given. We can't suggest any diagnostics because you give absolutely no information about what tells the drive how to operate.

 

[qinyong97]

External control is used to feed a signal to the drive, the drive is only needed to control the speed of the motor. Only DI1 signal is feed into the drive when we wish to run the motor in the forward direction (which based on the setting of 10.01 EXT1 STRT/STP/DIR = DI1,2). When we wish to run the motor in reverse direction, signals is send to DI1 and DI2, in which we have no problem in this scenario. Nevertheless, the motor will still start on reverse direction which goes up to around -220rpm for 6 seconds, then down to -137rpm which is our constant speed setpoint.

 

[Puddle]

Is the drive using the internal PID controller? This could cause it to run in reverse to try to achieve the setpoint before the process has fully started.

If so, parameter 40.20 is the PID sleep function, which can be setup to delay the PID control until running speed is established.

 

[qinyong97]

Is the drive using the internal PID controller? This could cause it to run in reverse to try to achieve the setpoint before the process has fully started.

If so, parameter 40.20 is the PID sleep function, which can be setup to delay the PID control until running speed is established.

40.20 is not visible since 99.02 setting in our drive is set to 'FACTORY', setting 40 only comes into play when 99.02 is set to 'PID CTRL' right?

 

[Puddle]

constant speed setpoint

What constant speed setpoints do you have?

Can you give more information what connections this drive is using?

Looking at parameter 30.01 there's a chance that the drive is defaulting to constant speed 15 on startup, but I don't know if you're using an analog speed signal or just fixed speeds.

 

[OkiePC]

I have seen other makes/models of drives do this when flying start is enabled and the drive, when asked to start, mistakenly detects that the motor is already running in reverse. If flying start is not needed, disable it. If it is needed, performing a more accurate auto-tune may help

 

[qinyong97]

What constant speed setpoints do you have?

Can you give more information what connections this drive is using?

Looking at parameter 30.01 there's a chance that the drive is defaulting to constant speed 15 on startup, but I don't know if you're using an analog speed signal or just fixed speeds.

The drive is actually use for screwfeeder, most of the time it requires to only run in forward mode, reverse mode is only required when its plugged. Its not really a big deal when it requires to run in forward mode, just need to wait 6 seconds everytime it startup for it to go to forward mode we have no issue after that, problem is when we want to unplug the screwfeeder and need to constantly jog between forward and reverse and the motor will constantly start on reverse everytime. We have other ACS drive for another application and seems to have zero issue (forward or reverse on startup as we wanted).

Constant is set on 137rpm on parameter 12.06 in this case, all the other parameters in 12.00 is set to 0rpm.

 

[qinyong97]

I have seen other makes/models of drives do this when flying start is enabled and the drive, when asked to start, mistakenly detects that the motor is already running in reverse. If flying start is not needed, disable it. If it is needed, performing a more accurate auto-tune may help

I will try to look into this.

 

[drforsythe]

Is the drive set up for Direct Torque Control or Scalar (see parameter 99.04)? If in DTC, the motor identification may not have been done properly. I have seen this on other drives where flux vector control was used. If it is in DTC, temporarily set 99.04 to Scalar and see if it still rotates in reverse at first. If the problem goes away, then you know it has to do with DTC and motor identification.

 

[qinyong97]

I have seen other makes/models of drives do this when flying start is enabled and the drive, when asked to start, mistakenly detects that the motor is already running in reverse. If flying start is not needed, disable it. If it is needed, performing a more accurate auto-tune may help

Turned out flystart was enabled from the autotune during initial installation, disabled it and the drive functions as how we wanted now.