SLC 5/05 and Powerflex 4 Drive Communication

Hi all,

I have been asked to build a panel with 7 Powerflex 4 drives.
AB Panelview 550
SLC 5/05 with digital inputs, outputs and analogue outputs if required.

My question is can the speed of the drives be altered by the PLC any other way than through analogue output cards.
Can it be done through DH485 port?

Any Allen Bradley geniuses that can help before I contact Tech Support and get told I have to use Powerflex 40 with Ethernet card etc?

You can set up a fieldbus communication link between the drive and PLC but I believe that would require a fieldbus module on the PLC.

Another thought if you don't want to use an analog input, is to set the drive for MOP (sometimes called Floating Point) speed reference input. This uses two digital or relay inputs, one to increase speed and the other to decrease speed. The problem with this is that the PLC has no way of knowing how fast the drive is actually running unless you take an analog drive output representing speed and send it back to the PLC to close up the loop. That requires an analog input card for the PLC.

If the PLC and drive are physically close to each other, probably the simplest would be to spring for the analog module and control the drive with a 0-10vdc signal.

Of course, I'm just a drives guy. Maybe some of our PLC experts here have a better idea. I'd be interested in that too for the next time I encounter this type of question.

According to the PowerFlex brochure that I have, it says that you can network up to 31 drives on a RS485 network. There is a serial converter module to be used with any controller that can initiate DF1 messaging.

This is from Publication 22-PP001B-EN-P

You can use the onboard Modbus interface to control the PF4. The downside is the Modbus card for the SLC is rather expensive, at least the Prosoft module that I used was. Using Modbus, you can write the speed reference and read the feedback signal, plus get the logic status data word as well.
Prosoft is at: http://www.prosoft-technology.com/

Prosoft Module

You'll want to look for the Prosoft MVI46-MCM, I have used this card with great success out of the SLC platform to other devices. The card is around $1,500.

Prosoft tech support has always been first class...

Greg

The simplest thing to use is a Modbus RTU Master module for the SLC, particularly the Prosoft MVI46-MCM.

The second simplest thing is to get a DeviceNet scanner for the SLC, and DeviceNet modules on the PowerFlex drives. If you're clever, you can run several drives per DeviceNet module (so-called Multi-Drive Mode).

That DF1/Modbus (22-SCM-something) converter does work and would be less expensive than a Prosoft module, BUT you have to be a pretty good A-B messaging programmer to efficiently message to seven drives.

Unless your time is very cheap, I recommend the Prosoft module.

I have made a programm that controlls 2 PF4 drives using Modbus RTU, but not on SLC.. I used Unitronics Vision120 controller.. It has build in functions for Modbus communications, so it was quite easy..

francevendee said:

Hi all,

I have been asked to build a panel with 7 Powerflex 4 drives.
AB Panelview 550
SLC 5/05 with digital inputs, outputs and analogue outputs if required.

My question is can the speed of the drives be altered by the PLC any other way than through analogue output cards.
Can it be done through DH485 port?

Any Allen Bradley geniuses that can help before I contact Tech Support and get told I have to use Powerflex 40 with Ethernet card etc?

Click to expand...

Due to the fact that you are using a 5/05, I would get the Ethernet/IP communication option (catalog # 22-COMM-E) for the PF4s. Now all of your control will be using the 5/05s ethernet connection. Easy.

Why don't you try devicenet, just install a devicenet adapter in your slc rack and you can connect up to 63 powerflex drives, the boards used for powerflex are 22-comm-d

Maybe I'm missing something here but, doesn't all this discussion make a simple analog card look pretty good! And simple!

DickDV said:

Maybe I'm missing something here but, doesn't all this discussion make a simple analog card look pretty good! And simple!

Click to expand...

Yes, that too, unless he wants a lot of control/status or the drive/motors are a long distance away.

If the DH-485 port on the Powerflex 4 is also known as a scanport, There is a 1203-SM1 Board (I'm pretty sure that's the number) That will plug into the SLC rack and communicate with the drives. I haven't used this on any Powerflex Drives, But I have interfaced with 1336PlusII, 8720MC, and 1397 AB drives.

The PowerFlex 4 and 40 series drives use a superset of Modbus RTU protocol that A-B calls "Drive Serial Interface", or "DSI".

It's not DH-485. It's not SCANport. It's not Drive Peripheral Interface (DPI) like on the 7-series drives.

I don't think there is a "DSI" module for the SLC platform, only for the 1769 Compact platform.

The simplest and most reliable way to implement drives communication in this system is to use the Prosoft MVI46-MCM module.

Thanks all for your comments and advise.
I think I will go with the Prosoft MV146-MCM module option.

Analog = simplest, maybe even the cheapest
Ethernet IP - next best. The price increase you pay getting the PF40's will be offset purchasing other cards like and analog or Prosoft card.

If you have never used the Prosoft Card, have fun While they are fairly reliable, they can be a PIA to set up.