# PowerFlex 700 Drive problem



## SergKom (Aug 29, 2017)

We have some damaged PowerFlex 700 drives with the same problem:
The DRIVE STATUS ACTIVE BIT(1), that PLC check in the drive(by Controlnet), sometimes becomes “0” and machine is stopped.
It happened 3-4 times in the day – sometimes more sometimes less.
More often it happened in the Start moment.

In the drive : Faults and Alarms - no any message, when it happens.
It was not communication problem : the damaged drive was swapped with working one – the problem follows the drive.

Somebody have any idea where the problem going from?


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## Jhellwig (Jun 18, 2014)

Do you have any unused digital inputs configured for something? 700's had issues with the io cassets getting fantom input signals. Disabling any unused inputs helps.


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## SergKom (Aug 29, 2017)

*PowerFlex 700 problem*



Jhellwig said:


> Do you have any unused digital inputs configured for something? 700's had issues with the io cassets getting fantom input signals. Disabling any unused inputs helps.


Hi,
thanks for your answer.
All unused inputs are disabled.

Regards
SergKom


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## bill39 (Sep 4, 2009)

SergKom said:


> We have some damaged PowerFlex 700 drives with the same problem:
> The DRIVE STATUS ACTIVE BIT(1), that PLC check in the drive(by Controlnet), sometimes becomes “0” and machine is stopped.
> It happened 3-4 times in the day – sometimes more sometimes less.
> More often it happened in the Start moment.
> ...


Post this on plctalk.net. It's a great site.
They have some AB/Rockwell guys who linger there and should respond.


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## JRaef (Mar 23, 2009)

In a 22-Comm card configuration for PowerFlex 7 series drives, the default for what happens if there is a loss of communications is a Fault sent to the drive, and if the "owner" of the Run/Stop command is the comm card, that typically shows up as a "Stop Asserted" command on the drive display and in the command string would look like that bit going to Zero. So most likely there is something interfering with your ControlNet signal. I would be looking for EMI/RFI problems in your ControlNet environment if this happens on more than one VFD. If it "follows the drive" as you say, meaning the same problem happens with the same drive, but not when you put in the new drive, then it's likely an issue with the 22-Comm-C card used for the ControlNet interface of the drive.


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