Connecting to PowerFlex 4 via 1747UIC Adapter

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Good Evening Everyone,

I tried to find pick through the forums and found some similar problems, but could not find quite what I was looking for.

I'm trying to connect to a PowerFlex 4 Drive via a 1747 UIC (Rev D) USB to Serial adapter using a Windows 7 32bit VirtualBox. I've installed the appropriate drivers, have the dip switch in the RS485 position and RSLinx (Version 3.60.01) recognizes the adapter, but I can't get RSLinx to browse/find my PowerFlex Module. The datasheet for the converter is: http://literature.rockwellautomation.com/idc/groups/literature/documents/in/1747-in063_-en-p.pdf

Trying to avoid buying the ~$400 1203-USB adapter at all costs.

My Setup: I have the adapter plugged into a usb port and it was assigned to COM3 (in the VM). I then have an RJ45 cable (Straight through) plugged in the front of the adapter and connected to the PowerFlex4 on the other side.

I'm aware that the PowerFlex 4 is programmable via the integral keypad on the front, but the PowerFlex 4 is more of a lab rat on trying to talk to the powerflex from my computer (as I will be connecting to a PowerFlex 40 P for a customer next week, which as you all are aware, does not have an integral keypad to program from). I was hoping to be able to program the PowerFlex drives using Connected Components Workbench, but have to be able to talk to it from my laptop first.

Any Suggestions?

Thanks in advance
 
Alan is correct; the 1747-UIC only supports DH485 protocol on the network side, whether over RS-232 or RS-485 wiring.

The PowerFlex 4 series uses RS-485, but the protocol is Drive Serial Interface (DSI). DSI includes several Modbus RTU commands, but it not limited to Modbus RTU commands.

The 1203-USB packs a lot more into its electronics than you might think; there's an RS-485 UART and a CAN transceiver, and protocols for DSI, DPI, and SCANPort.

But I can see how it would appear overpriced if all you need it for is DSI.

My recommendation would be to get a general-purpose USB/RS232 converter and add an RS-232/485 physical adapter to it.

I've used a Keyspan USA-19HS USB/RS232 converter in conjunction with the 1761-NET-AIC with success, though I don't remember for sure if I was talking to a PowerFlex 40P.
 
Thanks Alan and Ken.

I appreciate the elaboration, all of these serial protocols get confusing!

Ken: Prior to trying to use the 1747, I tried something similar to what you're suggesting. I have the following converter on my desk (http://e.sealevel.com/display.php?List=1&N=58) and terminated the D+ and D- to the respective wires (4- Blue & 5-White/blue) on an RJ45 straight through cable which I connected the other side of to the PowerFlex Drive's RJ45 jack. On the converter side, I placed the 120Ω resistor across the D+ & D- wires (per Appendix C, pg C1, of PowerFlex 4 series drives user manuals). I know you're supposed to have a 120Ω Resistor across the side that terminates at the drive as well, but wasn't sure how to go about that since it's crimped with the rj45 head... Also, I have the the shield terminal on the drive (16 on the 4 and 19 on the 40 &40P) connected to earth ground, as specified in Appendix C as well.

Do you know of any sites that explain how to send RTU commands or a reference to software that can send them using this method? I'm not extremely familiar with all of this (as you can probably tell), so any info helps. Thanks again, guys.

-Jeff F.
 
SeaLevel Systems makes great stuff.

Take a look at the fourth photo on the Sealevel terminal block's product page:

tb34-4_4.jpg


R+ and T+ together are equivalent to "Data A"
R- and T- together are equivalent to "Data B"

(Probably.)

Because RS485 nomenclature is a coin toss, always try swapping Data A and Data B. For a short cable you don't need to worry about termination.

Be sure you have the "Data Common" or "GND" for both the PowerFlex comms port and the Sealevel comms port connected together.

"2-wire" RS485 always involves a reference conductor. Sometimes it's literally Earth, sometimes its a chassis ground, and sometimes when when the birds are singing and the flowers are in bloom, both vendors supply an isolated data common conductor.

ModSim32 is the best Modbus RTU Master emulator on the market. I can always rely on it to do what it's supposed to do, and the demo version runs fine for quick tests.

There should be examples of how to address the PowerFlex 40 using Modbus RTU commands in the user manual and knowledgebase... I'd have to go re-familiarize myself with it but dawn is racing toward my shores.
 
Thanks, Ken. Long story short, we wound up having a 22-HIM-CS2 Module laying around in storage that I was unaware of, so after all day of trying to figure out how to use ModSim32, trying to make sure I had the converter wired right and trying to talk to the drive, someone found the HIM and it works like a charm. Learned a lot about the modbus RTU protocol in the process, so that's a plus.

Thanks for all of the info/help!

-Jeff F.
 
Now that you've had a taste of Modbus RTU and serial troubleshooting, you're going to want to do it all the time.

Welcome to the Forum !
 

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