Powerflex70 VFD - PLC reference

[teslanow]

I have an issue with a Powerflex70 drive communicating with a PLC5. The drive is setup as 1/2 rack and is communicating over remote I/O. It is only using the discrete I/O for control. The problem is with the speed reference. The drive starts/stops ok when the PLC tells it. The Start Owner & Direction owner shows 'DPI port5' as it should. However, the Reference Owner (param 292) shows all 0. I can see that the drive is receiving the speed reference in the Drive Ref Rslt (param 272). However the Drive Logic Rslt (param 271) only shows bit 1, and 4 (start & forward).

Can anyone tell me what would cause the drive not to use the speed reference even though the Speed Ref Source (param 213) shows as DPI Port 5? Its making no sense to me.
Any help would be appreciated.

 

[rdrast]

Do you have "Speed Ref A Sel" (P90) set to "DPI Port 5" (22), or whatever the RIO adapter is?
Speed reference high and low configured for Ref A?
Is unit set to Bipolar mode (for negative references) (P190, Direction Mode)?

 

[teslanow]

rdrast
Yes, P90 is set for 'DPI Port5 (22)' P190 is set for Bipolar.

Now...P91 'Speed Ref A Hi' is set at the default of Max Speed and P92 'Speed Ref A Lo' is set for 0 Hz. Is that a problem?

Thanks for the help.

 

[teslanow]

One other note: P2 'Command Frequency' is showing the correct frequency that the PLC is requesting.

 

[teslanow]

just checked again at the plant and I was incorrect about P2. It is showing what ever P82 show for max speed.
Thus the problem I suppose. ??

 

[kekrahulik]

In your output command word, check out bits# 14,13,12. They should be set to 0,0,1 to select speed referenceA. I suspect you might have those bits set to follow speed refB

As another fix, you can set drive param#93 to follow DPI port#5 as well.

 

[teslanow]

Kerkrahulick
I actually tried this on a hunch Monday night and it worked! It was bit 14. The strange thing is that we have 2 other Powerflex 70s and neither has that bit set. The only thing I can come up with is that maybe the firmware is different.
Thanks for your response! The lightning strike that caused all of the problems has kept me going non-stop. And I have been back on this site.. This site is great! Thanks for everyones help.