control 6 VFDs Power Flex throu Ethernet ?

[leonlai 0]

Hi folks, I am now encounter the problem that I never meet before, how can I control 6 VFDs which is connected (series jump) and all connected to a mini DIN AB 1763-NC01 ???? I usually work with Analog so I know the Address for Output control, however, in this case, how can I give them address and use it to control those VFDs ??? (Micrologix 1400) Thank for helping

[alan_505 24]

Your heading says that you want to connect through ethernet then in the main part you want to use a 1763-NC01 which is a RS-485 connection device. So which method do you want to use. Also which brand of VFD are you using, that will determine which network you use to communicate with them.

[OkiePC 14]

Using a controller designed for controlling I/O with EthernetIP would make this a piece of cake. The SLC and Micrologix families of controllers are not designed to control I/O using EthernetIP. It is possible to use explicit messaging to communicate with these VFDs using a SLC/Micrologix, but it is a kludge and is not recommended. Absolutely do not do this for your start/stop signals. We have a system (designed by a vendor) which had 9 drives set up for speed control using a SLC 5/05 and messaging. It was always unstable. Reducing the number of drives to 5 helped, and staggering the messages, increasing the network timeout limit in the drives and a bunch of other jumping through hoops made it pretty reliable, but not 100%. We finally did away with some of the equipment and deleted that code. The VFDs are now running at a fixed speed. We left the ethernet connection in place so we can use drive executive via the network to monitor the drives. The start/stop control has always been hard wired. I suggest you trade the controller for a Compactlogix or Contollogix unit or use hard wired controls for the VFDs. It is probably okay to use MSGs for the speed command and to read/write parameters, as long as your application can tolerate the delays that will be necessary to pull this off. More threads on the subject (pay close attention to posts by Mr. Ken Roach): http://www.plctalk.net/qanda/showthread.php?t=26178 http://www.plctalk.net/qanda/showthread.php?t=50284 http://www.plctalk.net/qanda/showthread.php?t=42236

[b_carlton 61]

The RJ45 socket on the Powerflex drives is not Ethernet. Is is an RS485 connection. Your description of the NC01 is reasonable. It is a wire breakout for the RS485 signals generated by the Micrologix 1400. The drives understand Modbus commands. Review the communication section at the end of the full Powerflex manual. The speed as well as other factors are easily controlled using MSG commands from within the program. If you are describing an already working system and you have the program look for MSG commands. Edited 18 May 2012 by b_carlton

[Bob A. 1]

When it is actually time to use EtherNet with PowerFlex Drives, there is an add on module that goes on the front that replaces the wiring cover. It will be called something like 22 CommE or 20 CommE, depending on model of PF. They work fine and it is possilbe to do control and monitoring via EtherNet, however, I still use the hardwired two wire on-off as a hardwired enable, controlled seperately via digital IO. As mentioned above, you would want to be in CompactLogix or ControlLogix for this. It is also possible to control more than one PF with a single 22 CommE. I've not tried it and would not impliment it because of potential confusion, but it is described in the manual. Bob A.

[b_carlton 61]

We control up to the limit of 5 Powerflexes from the COMM-E. But it is limited to sending speed and reading status. On/Off is still by hard wire. But, if we have our preference, we use RS485 Modbus. One Read message and one Write message per unit. The addressing of elements is much simpler. Ethernet is a pain from the 1400 since it doesn't do the I/O messaging. Oh, and we've controlled up to 14 Powerflexes from one serial port. Edited 20 May 2012 by b_carlton

[PLCMentor.com 60]

Nooooooooo! Been there and done that. What a mess. I was talked into it because it would be cheaper. The setup and design time involved eliminate any hardware savings and it is a permanent pain in the rear to configure and work with. It was kinda cool to put together and get up and running, but I would never let anyone talk me into that again. RS485 would be better. Almost anything would be better...

[leonlai 0]

Yes, all the Powerflex drives are connected serial by RJ45 and then to the NC01 card, this is a working Control Panel, and there is no program yet, so I wonder how come I will control them ?? how to assign them an address to give them an output control and speed control !? Thank you all guys

[b_carlton 61]

Again, read the FULL Powerflex manual (22a-um001-en-e.PDF - this is for the Powerflex 4). At the end are the communication sections (C and D). You will use MSG commands. Parameters A103 through A107 control the communication parameters. Set these then cycle power. Work on communicating with one. When you have that add other, daisy-chaining the communication twisted-pair and changing the node address so that they are unique. Another useful file is PF4ModBus-RTU_Note_&_Ex-Program.zip. Search for it at www.ab.com Edited 22 May 2012 by b_carlton

[bce123 0]

this statment really confusses me!!!