ML1400 to PowerFlex VFD

Since it's a MicroLogix 1400, use the Ethernet port for upload/download and troubleshooting. Far faster and easier than serial.

The DH485 protocol you are using with the PanelView is different from the Modbus RTU protocol you need to use with the PowerFlex drives. Even though they both run on the same RS-485 type of wiring, they are different and incompatible.

Does the MicroLogix 1400 support RS485 using a 1763-NC01 cable from the Channel 0 serial port (the round mini-DIN) ? That would be my choice. Otherwise you need another RS-232 to RS-485 converter like the 1761-NET-AIC.

I agree with Eddie in prefering ethernet. You can use CH1/ethernet on the ML1400. You will need an ethernet switch (unamanged). The panel view can also be on ethernet. This is a pretty easy application. Plus, you don't need the net aic module. But this route is not free.

You will need to purchase a 22comm-e card for each drive. These are ethernet communication cards that mount to the front of the powerflex. They are about $200 each. You will need one unmanaged switch as an ethernet hub. The unmanaged switch (5 port) is about $180. You also need a 24VDC power supply for the switch, but you may already have one.

You probably already spent some money and you're thinking that you don't want to spend any more money. Ethernet is a cleaner comm setup, easier to troubleshoot, and easier to augment in the future.

If you use modbus for the drives, you will have to use CH0 (serial) for the drives, and you will need a cable with a mini din on the PLC end and a terminal block on other end. This is for field connections. That's all you need to talk to many drives. The rest is field wiring. Modbus is great, just not as fast as ethernet. You can extract any parameter from the drive to the PLC, and you can change most. The problem is you still have to talk to the panelview. For this use CH1 (ethernet). This system will work well also.

EE

One item of note...
Any comms cabling to the VFD should be shielded. They put off a whole lot of EMI.

thanks guys for the response. First of all, the PV1000 was provided by the client so I had to get it to work with the RS485 interface and now that I have it working...dont really want to touch it. However, I hadn't really thought about using the ethernet to download the program to the PLC but thats an option I'll have to play with to get it to work. Probably a good thing to make sure since the client will more than likely be doing changes. I know the ethernet works as I ran a VB program to talk to the PLC from the PC. So back the the VFDs. I can't really afford $400 more on this project. The ML1400 does have com0 DIN connector for the RS485, so I am thinking this can be connected directly to the VFD then. I should be able to just strip back the wires and connect directly to the VFD RS485. Thats the project for this weekend get that up and running.

OK time for an update. Going with the suggestion of moving the programming over the ethernet, got that up and working thus freeing up com0 for the VFD interface. I have a 8pin mini din cable (PM02)but turns out they don't bring out the RS485 pins (what happened to pinning everything out???) so correct me if I am wrong, but it seems the only cable thats going to work for me is the 1763-NC01 with the terminal block connections. They don't make one that has a RJ45 on the end of it? Really?

OK so using messages. Not completely clear on these, basically I want to enable the VFD to run, set a specific speed value, and read back any error messages (polling I suppose for those). In the message setup screen its asking for MB data address, slave node address. I assume since I have to VFDs on this chain, one is going to be address 1 the other is address 2 ?

Anyone have some sample code thats running they wouldnt mind sharing? I very late on getting this done, keep getting pulled off to handle other projects.

Pins 1 and 8 don't come to the DB9 side of the 1761-CBL-PM02 because they are the +24VDC and DC Common pins on the MicroLogix 1000, 1200, and 1500 controllers.

The 1763-NC01 is a compromise; only a fraction of the time will you be connecting directly to just one DSI port, so they went with a connector that can be used with long-line DF1 or DH485 or Modbus trunks.

The code for sending Modbus messages to and from AC drives is part of the "Connected Components" toolkit and examples.


There is an excellent community-sourced example of controlling PowerFlex 4-series drives using Modbus RTU protocol here: