from the MVI46-MCM department...
drive control, Modbus RTU using MVI46-MCM & SLC 5/04
PLCs and related questions. topic
Posted by Jim on 27 August, 2012 - 1:29 pm
I have 3 different VFD brands I would like to control using Modbus RTU. I have a Prosoft MVI46-MCM card in a SLC 5/04 rack. I have successfully tested this card using the sample program, but am having difficulty understanding how to configure the Modbus commands for drive control.

The drives I am using are Reliance MD60, AC Tech MC1000, and Hitachi WJ200.

I have set up the drives using 9600 baud, No parity, 8 bits, 2 stop bits due to requirements of the Ac Tech drive.

The drive parameters are OK, I believe that the MVI46-MCM setup is OK, Port1 settings are OK, but I am having trouble setting up the Command list.

If anyone has used this card and is willing, I could use some help or sample code for a similar application. It seems like I am missing something very basic.


Posted by Steve Myres on 28 August, 2012 - 10:56 pm
I have some pretty good SLC code for operating that card that I should be able to find. Post your email and I'll send it to you.

Posted by Jim on 29 August, 2012 - 4:50 pm
> I have some pretty good SLC code for operating that card that I should be
> able to find. Post your email and I'll send it to you.

(a bit reluctant to post real email...
I can reply with proper email if you like)

Thanks for your help!

Posted by Steve Myres on 31 August, 2012 - 12:59 pm
Done! :)

Posted by jeff on 14 August, 2013 - 10:38 pm
hi there! can i also have a copy of the program?

here's my add...


Posted by ES on 4 September, 2012 - 1:48 pm
ProSoft actually has a training document for that card on their website that talks about the setup and configuration of the Modbus commands. Here is the link:

If that does not answer your question, you can contact ProSoft and they would be able to walk you through it.

Posted by Dayvie on 10 May, 2013 - 8:55 pm
SLC 5/03 5/04 and 5/05's all speak Modbus natively

There is no need to purchase a $ 1,500 Prosoft module

You only need make sure firmware of the SLC is version 11 or higher.

If you have older firmware you can upgrade it

A firmware upgrade is much cheaper and Code is much much easier to write

If Firmware is 11 or greater then Modbus is an option in the drop down for protocols along with DF1, Dh485, ASCII etc

I have upgraded many many 5/03 5/04 anf 5/05's to get the Modbus option working.

5/05 is a simple software upgrade

5/03 and 5/04's require a eprom simply snapped on the mother board of the CPU and it will upgrade the firmware

You only need to buy the EEPROM or the Software one time and can upgrade many processors

Both items are available to purchase from Rockwell.


Posted by Jim on 12 May, 2013 - 7:09 pm
Thanks for all the replies.

I already have the Prosoft card, so no need to pay for firmware upgrade.

Steve, I finally got around to checking out your code sample, but it was not helpful, I didn't even see the Prosoft card in the I/O config, only a Basic card.

To those who have sent the older 3150 samples, also no help, maybe I am too thick to understand.

I have just recently returned to this project after months of working weekends. I have run the sample labs from Prosoft after upgrading the firmware with success. I have read and reread the manual 12 times, It seems fairly simple but I am still missing something, perhaps a brain.

I have a Reliance MD60 that runs on 120V single phase to practice with, all the manuals, etc. I just cannot get the Prosoft module and drive talking.

I have tried address entry in decimal & hex, and now I am so frustrated I am just trying random settings. If there is anyone willing to take time to toss me some questions or info I would appreciate it.

Thanks again all.

Posted by Steve Myres on 13 May, 2013 - 12:57 am
My apologies -- that sample WAS for a 3150 (which at least at that time you had to configure as a BASIC card). I overlooked that you were using the newer MVI46 card.

Posted by Jim_ on 4 June, 2013 - 4:13 pm
> My apologies -- that sample WAS for a 3150 (which at least at that time you
> had to configure as a BASIC card). I overlooked that you were using the newer MVI46 card.

No problem, I appreciate the help.

I finally got around to playing again, and guess what I found....I had sometime in my foolishness tried to test COM2 port directly from an RS232 connection, set the card jumper, then forgot.

That means that all of my attempts to connect via RS485 have been frustrated! Just discovered this rookie mistake, and finally got connected to my Reliance MD60 drive. Beware, the MD60 requires the polarity reversed from what you see on the Prosoft pinout.

I can now dig in and I will post the results back as I go. I guess Dr. Leo Takahashi from Penn State was correct. RTFM. "Read the manual".

Posted by Jim_ on 8 June, 2013 - 10:45 pm
OK, had some success!

I have modbus connected, RTU 'flavor', RS485 networked to two Reliance MD60 drives, master is a MVI46-MCM module in a SLC 5/04 PLC rack.

I have managed to set up the MCM config, & Port commands for Read Status word, Read Speed Feedback, Write Speed setpoint/command, Write Logic Command word (start, stop, etc).

Currently from ladder logic bits, I can start and stop the drives independently, monitor the status, set speeds, monitor speeds, and reset faults.

My next task is cleaning up and organizing the integer and bit files in preparation for setting up the other drive types, and hopefully setting up a data file template for each type of drive, that I can use to standardize tag names, and get the Wonderware templates written.

I may mess around with the communications status data a bit, and drive parameters, the goal would be to transfer control from the network to the drives local HIM faceplates on communications loss (change command sources on network fail), without faulting the drives, (annunciate only) which would remain running at the last setpoint, and also to return them to network control, bumpless transfer, from an HMI.

I have one Hitachi WJ200 available but no Altech, regardless I cannot set them up, since I do not have 480V 3 phase in my home. Yet.

Anyone interested in the finer details, just reply here. I will post again with my "gotcha's" on the other drives.

Thanks again all who helped out. Hopefully I can return the favor some day.

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