LG iG5 Variable Frequency Driver Modbus-RTU

[maurosmartins]

Hello all,

I'm using a LG iG5 Variable Frequency Driver to control a blower. Now I want to control it using RS485, I've already connected it and I'm able to write to the register using modbus RTU.

nevertheless I have an issue, in the manual I've found that I must configure DRV-03 (dru) and DRV-04 (FR9) to be 3 and 5 respectively so that I can use modbus-RTU.

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with both options set to modbus-RTU I'm able to set the motor speed writing to register 5, but I'm unable to start and stop the motor writing to register 6.
If I set only DRV-03 to 3 I'm able to start and stop the motor but I can't change the speed.

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Do you have any idea of what can be wrong? how can I control motor speed and state simultaneously?

looking forward your reply,
Best regards, Mauro.
 

[tonyh88]

Seems like a rather odd behaviour. I'm not familiar with those iG5 drives unfortunately.

What software are you using to test?

All I can say is make sure you have all the parameters set correctly as indicated on the page 74 in the manual and i the below screenshot.

There seems to be a write enable (address 4) and also I/O50 that needs to be set to ModBus RTU. I didn't see any indications referring to the fact that both the start/stop and speed can't be controlled via Modbus at the same time so I would expect it to work.

Maybe try contacting the company if all else fail?

[maurosmartins]

Hello tonyh88,

thank you for your reply.

I have all parameters matching the manual also I've enabled write enable and I'm able to update the registers. Tomorrow I'll try more things, any ideas are welcome.

Best regards, Mauro.