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Old November 1st, 2006, 10:52 AM   #1
johnglancy
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Powerflex 700 Problems over Controlnet

Hello. I have recently finished school and am fairly new to PLC's. I am having a problem with our powerflex VFD drives. We are an older remote plant which encounters a high amount of Utility line supply problems. At some point before I became employed, there apparently was a line surge which took down a number of our drives. A new drive was ordered and installed, but has yet to become operational. Here is some of the system specs. On this rack we are using a Logix 5555 1756-L55 unit, ControlNet bridge, 20-Comm-C adapter, and an AB Powerflex 700 VFD (non-vector) drive 20B D series A fw:3.002. One of our main issues is that the old .dno parameter configurations for the drive have been overwritten with the parameter file of one of our other powerflex 70 drives on the same rack(not sure how that happened....). We have rebuilt the parameter list to the best of our ability. Most of the parameters such as communication settings have been derived from the configurations of the other VFD drives on the rack. We just changed parameters such as nameplate information. When recently trying to go online with the drive we found that all status lights for the drive and communications are good, and the drive is recieving the hz speed septoint change(commanded freq. is changing on the LCD HIM). We just cannot get any output to the motor.

This is most likely not enough information for you guys to troubleshoot. Im hoping that somebody might catch something obvious. I am also wondering if anyone can give me sort of a check list for installing a new drive into a system like this. Our Rockwell TechConnect P.O. is in process, which may take a few more weeks and the engineer that was helping me with this issue has just changed positions so I am a little stuck.

I was thinking the problem may lie with one of the following: 1. parameter list i\o start\stop control is misconfigured. 2. EDS file may need to be updated if this is a newer version drive. 3. Needs to be remapped with the scheduler.

Please let me know what you guys think about this. I am a newbie so dont hesitate to educate me =].
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Old November 1st, 2006, 11:06 AM   #2
shahn4
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I have used these drive though Ethernet.

You may want to check Drive Parameter 209, 210 and 214 when trying to run from the PLC. It sound like you may not getting run command.
Also check Para 90 to see if it is set for proper DPI port for drive control.
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Old November 1st, 2006, 11:07 AM   #3
Ken Roach
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The drive is in the "I/O Tree" in RSLogix 5000, and the second tab for the drive's entry will tell you the current status of the connection over ControlNet. If the network needs to be scheduled, or if there's an addressing problem, or if there's a size mismatch or firmware mismatch with the I/O entry, that will be indicated there in the Connection tab.

If the drive appears to be taking a speed reference from the controller (the Commanded Frequency changes on the drive when you change it in the controller), then you definitely have a good network connection.

Does the HIM module have a "Stop Asserted" condition displayed at the top ? Sometimes there is another adapter or discrete input device that is telling the drive to Stop (usually it's Discrete Input 1) and that trumps the controller's Start command.

Also realize that the start and stop commands from the controller are "momentary"; they require a false-to-true transition. The normal condition is Stop =0 and Start =0. To start the drive, set Start =1, and to stop the drive, set Stop = 1. Usually I program the Start command to "set start = 1 until Running = 1" and the Stop command to "set Stop = 1 until Running = 0".

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Old November 1st, 2006, 12:52 PM   #4
johnglancy
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thnx for the reply.

I am waiting on our local activation (included with techconnect contract) for my copy of RSLogix 5000, so I will have one the remote process engineers check on the drive status.

I went down and looked at the drive HIM and yes there is a "Stop Asserted" condition displayed at the top. I am not sure what you mean by a another adapter or discrete input device telling the drive to stop. Can you give me a little more information on this? Would there be status bits on some of the parameters to indicate where the stop would be coming from?

I appreciate your help, thank you
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Old November 1st, 2006, 12:58 PM   #5
shahn4
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If the Parameter 90 is set for DPI port 5 then the stop command is comming from you PLC through control net. Make sure the HIM Stop is not pressed in.
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Old November 1st, 2006, 07:49 PM   #6
kamenges
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Quote:
Originally posted by johnglancy:

I am not sure what you mean by a another adapter or discrete input device telling the drive to stop. Can you give me a little more information on this?
The PowerFlex drive can accept commands from several different sources. One of those sources is the digital I/O on the drive. The other sources are the DPI ports. To a certain degree DPI ports are a logical construct. DPI (Drive Programming Interface, I believe) is the communication protocol used to talk to the drive. You can have multiple DPI ports active on the drive at the same time. They all have equal priority. As stated earlier, stops trump starts.

Look at parameter 288. This parameter will show you the source of any stop commands seen by the drive. Bit 0 is the digital input, bits 1-5 are for DPI ports 1-5. As stated earlier, the comm module will be on DPI port 5 unless it was specifically changed. If you have a manual you can get the bit pattern from there.
Good luck.
Keith
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