ML 1200 to PV550 and Powerflex 4

[controlfreak810 0]

I have a networking situation that I could use some help with. I have a Micrologix 1200 that I need to connect to a Panelview 550 via DH-485 and a Powerflex 4 drive via 22-SCM-232. My thought is to connect port 2 on an AIC+ to the Micrologix, port 3 on the AIC+ to the Panelview, and port 1 to a 22-SCM-232 to the Powerflex. Two questions: #1 will this work? #2 Can I connect the Powerflex 4 DSI port directly to DH-485, and ditch the 22-SCM-232? Thanks in Advance

[Eddie Willers 2]

DH-485 is NOT the same as RS-485. That's the fundamental problem here. The MicroLogix 1200 has a multipurpose RS232 port but the protocols supported by your PanelView and PowerFlex 4 are incompatible. The PowerFlex 4 supports only "DSI" protocol on RS485, which is essentially Modbus RTU Slave. The PanelView supports DH-485, which is an A-B proprietary protocol. The MicroLogix 1200 can run six different serial protocols (RTU Master, RTU Slave, DF1 Full Duplex, DF1 Half Duplex, DH485, and ASCII) .... but not two different ones at once. If you had a MicroLogix 1500 LRP with two serial ports, this would be do-able. One port could be set up for DH485 to talk peer-to-peer to the PanelView, and the other could be set up for Modbus RTU Master to command the drive. But with a MicroLogix 1200 and just one serial port..... you're going to have to run the drive with discrete and analog signals, not with a network. I think it's foolish for A-B to offer drives that don't use an A-B protocol like DH485 or DF1, but that's what the super-cheap drive market is like.

[controlfreak810 0]

Thanks for the info! Didn't think it would be that easy!!!! I just found out today that there are going to be some additional duties for this project, and I'll be "upgrading" to a SLC 5/04. Now I can put my PV on DH+ and free up the serial port for the drive.

[Eddie Willers 2]

You're still not quite there. The PowerFlex 4 microdrives only communicate using Drive Serial Interface (DSI) protocol, which is basically just a subset of Modbus RTU protocol on RS-485 multidrop wiring. The MicroLogix 1200 and 1500 now have built-in Modbus RTU Master protocol available on their serial ports, but the SLC-5/0x controllers do not. If you want to control this drive serially from an SLC-5/04, you will need a Prosoft Modbus Master card or some other way to convert from an A-B protocol to Modbus RTU Master.

[controlfreak810 0]

I guess I should've been a little more clear, when I said that I could free up the 5/04 serial port for the drive. What I should've said was that I could free up the serial port on the 5/04 for the 22-SCM-232 to control the drive. I ran the drive with this setup today and all is good. Thanks for all your help!!!