ML 1400 to MODBUS to PowerFlex 4M

[kandanews]

Evening all,
Can someone please tell me (i know the manuals say it is possible), if MicroLogix 1400 PLC will communicate thru 1763-NC01 cable to a PowerFlex 4M drive?
I have been reading manuals on modbus, pf4m, ml1400 for weeks. everything is there for it to work, but the manuals say "if the device supports these modbus functions, it SHOULD work"..


thank you,
Ken
ps. oh, and if so..... what the heck am i doing wrong?? ( and i got the only knowledgebase item i can find (handshake is not enabled) )
and i will gladly provide many, many more details if this is a possible thing to do.

 

[AJZ]

See AB Knowledgebase articles 33774 and 33264

 

[kandanews]

thank you AJZ,

I have read both of those articles, and neither tells me if ML 1400 works with MODBUS to control a PowerFlex 4m drive.

I have everything set up as detailed in both of the articles, except of course that i used the parameters for a 4M which are different.

 

[Kidblue]

Ken,

What you are trying to do WILL work (we have several system doing exactly that), but as several other members have (and probably will again!) point out, it's probably wiser to control the 4M hard wired and maybe use the modbus for status/monitoring.

It is possible to fully read & write to the drive via modbus, but is not recommended because of communication reliability isues.

Not sure which bit you are stuck at, but i can confirm what you are trying to do is definitely possible!

Hope this help!

Rob

 

[kandanews]

it's probably wiser to control the 4M hard wired and maybe use the modbus for status/monitoring.

i wouldn't mind hardwiring, but i'm testing this on a 2 drive machine, and once I have it working, i need to implement the monitor and control into a 12 drive machine. the only "control" i want is to adjust the speed periodically (2 or 3 times a week), and to clear "annoyance" faults that occasionally pop up without having to open the cabinet. we have a very wet atmosphere with misted water. And the powers that be (the ones that sign my paycheck) want a touch panel to set the speed.

Could you elaborate on the hardwire angle, and any other advice would be greatly appreciated.

Thank you,

Ken

 

[Kidblue]

Ken,

Check here to give you some pointers on best practice for controlling your drive(s).

Basically, all you need is your ML1100/1400 set as Modbus MASTER, connnect the 1763-NC01 to the 8-pin mini port, wire the A+B terminals to pins 4+5 of the RJ45 port of the PF4M (we use the AB plug adapters [Ak-U0-RJ45-TB2P] for ease) - see attached image. Then just use MSG blocks to READ or WRITE to the drive (the manual isn't too clear, but we read back the O/P voltage, Current, Freq, Bus Voltage, Set Freq etc to display on the HMI). You can also read back the Status bits (ramping up/down, at set freq, fwd/rev etc).

Hope thi helps. There are several sample bits of code from Rockwell if you search (if not, let me know and i can email them).

Regards,

Rob

 

[Clay B.]

Little Off Topic

As you said you want to control the drives via Modbus. As others have stated using the PLC to do this can cause problems due to the unreliablity of the messaging Comms. THis is a big issue and usually has people alot balder by the end of the project.

In my case the way I get around this is to make use of my HMI. Specifically a Red Lion G3 series HMI (actually the only one I have done it on). I use the HMI to talk Modbus to the drives and use data from the PLC to control. This way my comms are dedicated and the usual timing issues are greatly reduced.

Basically what you do is set a piece of script that runs whenver the comm port is called in the Red Lion and you data is passed.

Like I said this is a bit off topic and may not work for you but I figured you might want some options.

 

[kandanews]

Evening Everyone. The display is done and worked nicely. It was for a dog and pony show to prove that it could be done. It is all put away and i was told to order what i need to make the 12 drive display.

Thanks for all the assistance.

Ken E.