We are using a Mitsubishi Inverter A800-E series, specifically the FR-A820-00105-E1N6 option, with the built-in Ethernet card. This VFD is connected to a PLC, the Beijer PLC XP-340. For our application we are using two VFDs, each of them connected to the PLC, but that is not relevant for the discussion below.


This PLC is on charge of commanding these two VFDs and we have decided to go for modbus for its simplicity, and for the easily available that all the parameters of the VFDs are. We have been able to set up a modbus client in the PLC and read any parameter of the VFD, but we are missing two very basic steps before we can start testing motion:

- How can I set up the speed reference of the VFD over modbus? I have gone through the list of parameters one by one, read the list of parameters one by one and I could not find such a parameter. For instance, let’s say I want the motor to move at 1500 rpm. Where can I enter this information to tell the VFD to move the motor at that speed?

- How can I tell the VFD ‘go’ or ‘stop’. This is, how can I command it? I have seen something in bits 0-8, but I cannot wrap my head around this.

We are not familiar at all with PLCs and VFDs, and we are learning as we go, so apologies in advance if the questions above are too basic or if we are missing something very basic (which I think we are).

The manuals I have been reading can be found in:

- Inverter: https://emea.mitsubishielectric.com...00/fra800e/fr-a820-00105-e1-n6.html#downloads

- PLC: https://www.beijerelectronics.com/e...ontroller/BCS-XP340#smartengineeringresources

 

The registers you must write to in order to run/stop and control the frequency of the VFD via Modbus/TCP can be found in the FR-E800 Instruction Manual (Communication)
https://dl.mitsubishielectric.com/dl/fa/document/manual/inv/ib0600871eng/ib0600871engl.pdf

Page 100 details the relevant registers.

Additionally, you also have to reconfigure the drive's operation mode, command source, and speed reference source to allow controlling these via Modbus/TCP. I believe these are parameters Pr. 79, Pr. 338, Pr. 339, Pr. 340, Pr. 550, and Pr. 551. Refer to section 10 in the following FR-E800 Instruction Manual (Function):
https://dl.mitsubishielectric.com/dl/fa/document/manual/inv/ib0600868eng/ib0600868engm.pdf

 

The registers you must write to in order to run/stop and control the frequency of the VFD via Modbus/TCP can be found in the FR-E800 Instruction Manual (Communication)
https://dl.mitsubishielectric.com/dl/fa/document/manual/inv/ib0600871eng/ib0600871engl.pdf

Page 100 details the relevant registers.

Additionally, you also have to reconfigure the drive's operation mode, command source, and speed reference source to allow controlling these via Modbus/TCP. I believe these are parameters Pr. 79, Pr. 338, Pr. 339, Pr. 340, Pr. 550, and Pr. 551. Refer to section 10 in the following FR-E800 Instruction Manual (Function):
https://dl.mitsubishielectric.com/dl/fa/document/manual/inv/ib0600868eng/ib0600868engm.pdf

Hi, this is exactly what I am looknig for, but my VFD is FR-A800 E Series, not the FR-E800.

 

Sorry, my mistake. I saw the E and went straight to FR-E800, not E meaning the Ethernet version of the A800. However, from a communication standpoint, I believe the F, A, and E drives are all nearly identical, so everything I said previously applies to all 3 types of 800-series drive.

Here are the appropriate manuals for the FR-A800 E:
A800-E / F800-E Ethernet Function Manual
https://dl.mitsubishielectric.com/dl/fa/document/manual/inv/ib0600628eng/ib0600628engd.pdf
Page 78 (page 79 in the PDF) has the Modbus registers.

FR-A800 Instruction Manual (Detailed)
https://dl.mitsubishielectric.com/dl/fa/document/manual/inv/ib0600503eng/ib0600503engm.pdf
Page 389 (page 390 in the PDF) has the operation command and frequency command details.