Power Flex Drive Question

[Steve G 1]

I was asked to day if any of the power flex drives could feed two different motors of different sizes. They would not run at the same time, but be switch on different times. It was asked if the drive could load different motor parameters into the drive motor data fields through plc Logix and then switch the two motors on. They told me that the siemens diver was able to do this, and not knowing siemens I can not confirm this, so I am not sure if the AB power flex drives have this feature. I looked through the parameters and read the manuals on the pf 70 and pf 700 drives and could not see anything. Is this possible to do in the drive or could you use the HMI to load different motor data into the drive, I know you can save different drive parameters into a 20-HMI under different file names, but can you tell the 20-HMI to load the drive with the different parameters using Logix. The PLC attached to it is a Control Logix plc, 1755-L61. Thanks for the input

[Ken Roach 194]

In the PowerFlex 700 and PowerFlex 70EC drives, such a feature is called "Dynamic User Sets". You can store three sets of different drive parameters and select between them using discrete inputs or by setting the value of Parameter 206.

[BobLfoot 302]

Nice feature to know about. My only concern would be the NEC Regulations for Overload protection and such. How do we assure that Large Motor A parameters are not accidentally used with Small Motor B creating a hazardous situation. Ken does RA have a tech note / guideline manual for setting up Dynamic User Sets to comply with NEC's requirements?

[Ken Moore 23]

You could always install additional overload protection on each "branch". I like the discrete input option, that way you could have at least two people verify the drive settings, and then manage the change with a switch and sign off sheet.

[Steve G 1]

Thanks guy you rock. It is good to know that there is an option that will allow you to do is. I also brought up the concern to them about setting the wrong drive parameters with the wrong motor and they told be that the have put drive load side contactors with feedback on them and interlocked it in the plc code to not allow a start of the drive if the wrong contactor was selected Thanks again

[Ken Roach 194]

Important: The standard PowerFlex 70 drives don't support User Sets; only the "Enhanced Control" PowerFlex 70EC and the PowerFlex 700 drives (the "Series B" or "VC" type) have that feature. I don't know if the newer PowerFlex 753 or 755 drives support this feature. Your friendly neighborhood RA distributor should be able to help with that. While you could in theory implement the same kind of functionality just sending messages to the drive, the built-in User Sets have the benefit of not relying on user programming, and having built-in consistency checks and feedback about which User Set is active.

[paulengr 44]

PF 750 series supports up to 4 user sets. As far as I can tell, the PF 75x series is intended to eliminate most of the PF 70/700 series drives. It modularizes the drive even more than the cassette ports on the 70/700 so Rockwell can compete with other manufacturers in terms of price points while maintaining the feature set of the 70/700.

[slcman 9]

A cheaper way is to use comm for write parameter to PF4M drive with parameter C307 set to 1 (write to RAM). Use plc to send parameter for motor you need to use, do a read for confirm then run the motor.

[Steve G 1]

Just an update to my question and the answers I got, that's guys. I spoke to a AB guy I know, and he told me that is all correct, the only thing he cautioned is the number of time you change the setting due to the fact that the settings write to the internal ram of the drive and could destroy that ram if used to many times and at a fast cycle rate. Just though I would post this if anyone is interested. When Done it is prefered to use explicit messageing to do this, while the drive is in a no run state. Edited 8 Mar 2011 by Steve G

[Ken Roach 194]

I am surprised by the claim that changing the User Parameter Set value performs a write to Nonvolatile Memory. Can you get clarification and documentation on that ?

[slcman 9]

I attach C307 parameter detail from PF4M manual. This feature is not available for older firmware....not sure but I think it available at firmware 6. Edited 8 Mar 2011 by slcman

[Ken Roach 194]

I think we have two different but related topics here. The original topic was about the larger Architecture-class 7xx series drives and User Sets of parameters. PowerFlex 4M/40/400 drives can select whether parameter writes go to RAM or NVRAM based on a settable parameter. The specifics of which parameter number differ by model and there are some minimum firmware revisions. RA Knowledgebase Document 39880 (Access Level : Everyone) has the details. PowerFlex 7-series drives write to NVRAM or RAM depending on the message command code. Writes to the ordinary Parameter Object (Class 0x0F) write to NVRAM, and writes to the DPI Parameter Object (Class 0x93) write to RAM only. RA Knowledgebase Document 41550 (Access Level: Everyone) has examples and screenshots. Some PowerFlex 7-series drives (70EC, 700VC, and 75x) support the User Parameter Sets feature, which copies whole sets of parameters from NVRAM into RAM. It has a "Normal Mode" that allows parameter writes to be saved to NVRAM, while the drive is being set up, and also a "Dynamic Mode" that prevents writes to NVRAM. I believe this includes causing writes to the Parameter Object to also not be saved to NVRAM. This is where Steve G's technical rep and I might be misunderstanding one another. The RA Knowledgebase Document 32268 (Access Level: Everyone) has an excellent illustrated description of how data moves between NVRAM and RAM in the Normal and Dynamic modes of the User Sets feature.

[Steve G 1]

Good day to you all, I have tried to contact my guy for a couple of days but have not been able to reach him. Ken this could be where the confusion starts. When I hear from him I will post.