FX5UC - VFD (F840) Modbus implementation

2 posts in this topic

Dear Forum,

I am working on a set of "drivers" for some VFDs and wondering about you guys experience with it.

The system layout is as following:

FX5UC RS-485: MODBUS-RTU RS-485, lets say with 1x Mitsubishi F840, could be other drives (one drive per FX5UC)
Ethernetport: Connected to GT2510, using Freqrol driver
Another setup is for some other reasons not possible.

I want to have one PLC program for different connected VFDs, scheduled VFDs at the moment are: Mitsubishi F-840, ABB ACS880, Toshiba L.V. VFD, Toshiba T-300MVi.


What I want to do:

Read & Write status information - done.

Read monitoring values - done.

I want to setup some VFD parameters via the HMI. Send the parameter to the PLC and from the PLC to the VFD.
The parameters are "basic VFD parameters", every VFD should have, such as: Torque boost, accel/decel time, min/max frequency, base voltage/frequency, etc.

Of course these parameters are not simple Pr.0 to Pr. 125 but spread all over the place.
I want to check for min. and max. limits inside the PLC before transmitting the data to the VFD.

Knowing "basic parameters" will turn out quickly to "VFD specific parameters", I want to be prepared on the programming side.

The APSRW for read/write parameters are called through the program and hand shakes with other APSRW calls.


What would be a good approach do to the above? 

I rather invest more time into the PLC programming rather complicated HMI-Handling.

Reading simple 125 words and the next 125 words, then writing 125word and again the next 125 words?
Reading / writing individual parameters?
Reading / writing 125 parameters at once?

Any other approach for implementation?


Best regards,



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For the Mitsubishi Drives you could also use  CC-Link IE Field basic ofc but i Guess you woudl like to be able to choose wiichi drive,

So modbus TCP/IP is usually supported by most brands and you would have accees to all hardware remotely via ehternet if needed.

As for your parameters. I would create my own (companion spec) So my list of params I would to like to use. 

Once created I would then only write a program which send this list to the correct modbus locations depending on the brand(s). (reorder the list so to speak)
Then have a universal program again to send all the data to the drive if possible. (maybe a different modbus starting adress is needed)


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