Powerflex 40 to 1747-UIC

[Nesikep 0]

Hello, I'm looking to connect and control a powerflex 40 drive from a PC, I have the drive, I have a 1747-UIC (A, rev C, frn 1.3) which has an RJ45 port, like the drive. From what I am reading, I should be able to make a connector cable using only pins 4 and 5... it sounds like a piece of telephone cable would be perfect for the job, I have the crimper and ends. Do I need a termination resistor? One or both ends? Part 2 is going to be harder. From what I'm reading, it should be perfectly possible to 'talk' to the drive and get information back from it via any serial communication device, which means I shouldn't need RS linx. I'm looking to control it through a program I'll yet have to write in VB.net, but I'm not good enough at it to be able to do the low level communication.. Anyone know of a driver or library that can act as a go-between? I've been out of the PLC game for quite some time now... I'm going to have to do some relearning Thanks

[Ken Roach 194]

The electrical wiring standard is the same, but the protocol is different. The 1747-UIC runs only Data Highway 485 (DH485) protocol on the network side. This is a protocol that's specific to Allen-Bradley SLC-500 and MicroLogix controllers. The PowerFlex 40 runs a protocol called "Drive Serial Interface" (DSI). It's basically a superset of Modbus RTU. All the basic functions of the drive are accessible as Modbus RTU functions. If you're going to control a PowerFlex 40 from a PC, I recommend a general-purpose USB/RS485 converter and a Modbus RTU Master software library.

[kaiser_will 65]

Mimicing PLC comms to a PowerFlex 4 may be a challenge. Have you considered discrete control of the drive? I believe the PF4 has discrete inputs and outputs; you would only need a discrete I/O board plugged into your PC, controlled by your VB code. This is probably alot easier to accomplish.

[Nesikep 0]

From what I gathered in the literature, you *should* be able to request the data at a specific address on the Powerflex 40, and it should send back what is at that address, this would be for monitoring, To control, you would write to the address. The problem I have with a discrete IO board is I wouldn't be able to control ramp times, etc, and it would be a lot more limited. As it stands, this one powerflex is used on a LOT of different equipment, from stirring machines, to lathes, mills, and grinders, so going through all the parameters on the blasted keypad takes forever, if I could control it via a VB.net application it would be very easy to switch it all. What is the name/model of a good general purpose converter like you are speaking of? So from what you're saying the 1747 UIC is useless to communicate with the PF40, right?

[Ken Roach 194]

The 1747-UIC is meant for a different network and a different application. "Useless to communicate with the PowerFlex 40" is another way to put it. A-B has their own USB to DSI interface used with the Drive Explorer and DriveTools software, the 1203-USB. It's more expensive because it also includes CAN circuitry to talk to SCANPort and DPI based drives as well as the RS485/DSI PowerFlex 4 series, and because it supports a superset of those SCANPort and DPI functions instead of ordinary Modbus RTU. If you're just doing maintenance work, I don't see a reason to re-invent the wheel even if axles are inexpensive. I would just use Drive Explorer and a 1203-USB. I don't understand if you're trying to create your own control system, or just maintain and diagnose components in existing control systems.

[Nesikep 0]

Well, driveexplorer is no longer supported by AB., trying to download the connected workbench, I'll see if it'll do what I want it to. I'm looking to control it through VB, partly as a programming excercise, and because I kinda doubt there are cheaper ways of doing it. If it works through a COM port, I ought to be able to do it, I will have to create the packets according to the protocol indeed for it to be understood, but I dont' think that's rocket science as long as there's documentation. The long and the short of it is I have one drive doing a lot of things, sometimes it's doing step logic, and with a bunch of different parameters, other times it will run a PID loop, all depending on what it's connected to. I'd like to be able to create a file of the parameters, have a good interface with sliders that I can easily change, etc..

[Nesikep 0]

OK, looking at prices for a 1203, nothing under $200.. someone mentioned generic ones? What should I search for?

[kaiser_will 65]

Consider this other alternative...simple A-B PLC controlling the PowerFlex drive via Ethernet/IP. If you lave RSLinx OEM or RSLinx PRO communication software, you can easily code Excel DDE poke commands to change drive parameters via the PLC to the drive. I would go with a simple CompactLogix PLC, a 1769-L16ER-BB1B. Ethernet into a 4-port switch, that is also connected to your PC. Install RSLinx OEM or PRO on the PC with Logix5000 or Studio5000. This is how a machine builder would go about it. A-B drives have not lended themselves to direct programming, that I know of.

[Nesikep 0]

OK, that could be workable, I think I still have a working RS Linx Pro around.. Been years since I installed it, and have never had in on a Win7 x64 machine, so maybe I have to dig out my old XP laptop from years ago to do this work. AB and Autodesk, two companies that make life a MISERY when upgrading computers or their own software.

[kaiser_will 65]

To deal with the issues of different software on the same PC causing grief, consider virtualizing your Allen-Bradley/Rockwell software in a separate VirtualMachine. I have been using VMWare Workstation for years for this task. You can download VMWare Workstation free for 30 days to use (about $250 to buy, one-time license on that PC).