REXYGEN Community Forum

mikeyh

Member

From: New Zealand

Registered: 2016-04-28

Posts: 44

Modbus Registers

Hi All,

I'm having trouble getting the Modbus on the Monarco Hat to communicate to a specific controller. I can't see where I'm going wrong and all wiring is correct, so i assume my register map is incorrect. Project enclosed, Modbus register address doc is also in the folder.

Just wondering if anyone can see anything obvious.

Cheers

Mike

Controller-Logger_Dixell.7z

tomáš čechura

Administrator

Registered: 2016-02-22

Posts: 371

Re: Modbus Registers

Hi Mike,

I don't see any issue. What does the System log say? Is there any error regarding Modbus communication?
I noticed you specified the Modbus addresses with -1 offset in REXYGEN, am I right? Did you try not to use the offset and configure the mapping according to the datasheet?
What is the Slave address?

Cheers, Tomas

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Raspberry Pi as a miniature industrial PC. Analog and digital I/O, RS-485 and 1-Wire bus.

mikeyh

Member

From: New Zealand

Registered: 2016-04-28

Posts: 44

Re: Modbus Registers

Hi Tomas,

The log says "MBDRV: Slave 1 not responding (item='probes')".

The -1 offset was me just trying different things to see if I could trick it to work..! I had tried 0 zero offset we no joy.

Slaves address is 1

Cheers, Mike

tomáš čechura

Administrator

Registered: 2016-02-22

Posts: 371

Re: Modbus Registers

Hi Mike,

"Slave X not responding" means that the communication with slave wasn't successfully created. The reasons can be:
- wrong communication parameters (baudrate, parity, ...)
- wrong wiring
- wrong Slave ID (slave address)
...

Do you have any working example with the controller using a 3rd party software for modbus communication? Just to be sure that the parameters are correct.

Cheers, Tomas

---

Raspberry Pi as a miniature industrial PC. Analog and digital I/O, RS-485 and 1-Wire bus.