Modbus RTU between FR-800 and QJ71MB91

[ducna 1]

Hi everyone,

I'm trying to setup connection between FR-E800 inverter and PLC 03UDVCPU via QJ71MB91 module.

I have a problem where the modbus module keeps ERR led. In the error diagnosis, there is a message 7360. 

I can't control inverter with QJ71MB91 module.
Then, I tried  to control the inverter with RS485 cable and PC. It works. However, the connection seems unstable, often with the message "l llegen response" in "Write and Read" mode.

Can u see my module configuration and give me some suggestion?

Thank you very much!

 

Edited 17 Aug 2023 by ducna

[ducna 1]

Hello,

Is there anyone know this case?

[Goran Vuckovic 15]

You should use h06 or h10 for writing holding registers.

[ducna 1]

Hi @Goran Vuckovic,

Sorry I'm a newbie :))

Can you open more your suggestion.

I had seen some video on the youtube that they're configuring the QJ71MB91 by Intelligence function. The didn't use the code.

[ducna 1]

I have solved my problem. Here is a video that suggested the way for me.

https://www.youtube.com/watch?v=bob00fG5lXs

I need to address in Intelligence function module as: Target MODBUS Device Head Number = Address target - First address(40001)

However, there is still a long way to go. I cannot access multiple register addresses on the drive at once. For example when I put:

- Target MODBUS Device Head Number: 8

- Access Point: 1

Everything works fine. But when I set Access point = 6 (because I want to use target modbus: 13) the connection to this address fails.

Thank you everyone.

Edited 21 Aug 2023 by ducna

[Gambit 326]

The FR-E800 support up to 125 registers. However i see that there are some gaps in the holding register 

Set the holding register address from which to start reading the data. 
Starting address = start register address (decimal) - 40001 (Except for the CiA402 drive profile)
For example, when starting address 0001 is set, the data of holding register address 40002 is read.

Edited 29 Aug 2023 by Gambit

[ducna 1]

Hi @Gambit

Thank you for your answer.

There are some gaps at address 40011, 40012, 40013.

So I have to use 2 sets of parameters to read/write to 1 inverter.