Read / Write Modbus

[TonKro]

I am trying ro read / write registers via modbus but the EVSE does not answer.

• Configured 8600 8 N 1
• Checked the bus if the data is there, which is
• Eg ty to read out register 1

Send out: [1,4,0,1,0,1,96,10]

Also tried as other Unit-ID like 2: [2,4,0,1,0,1,96,57] (this data is showed as decimal)

No answer from the Smart EVSE.

When enable Smart / Loadbalancing. The data is there and working correct between the EVSE and Sensorbox.

What am I doing wrong? What does the EVSE expect?

[bobosch]

Which version of SmartEVSE do you use?

[TonKro]

Good question, the specific version I do not know, I did purchase it via stegen.com on the website like 1-2 Months ago assuming I got the most recent version by then.

BTW: The invoice does show v2.2

[mstegen]

When you enter the setup menu, the software version should be visible on the LCD.
The version is also shown when powering up the controller for two seconds.

[TonKro]

Thanks.
Just checked, it is indeed v 2.20

[bobosch]

Please use this modbus manual
https://github.com/SmartEVSE/SmartEVSE-2/tree/b8b6a1a2def22a2bfc3cc30be2f2ef639e2d4389#register-for-external-devices

Try to read register 0x00A0

[TonKro]

Which Unit ID should be used?

[bobosch]

It should be 0

[TonKro]

As far as I am aware of could the unit id only from 1-255?

[TonKro]

Maybe you can share a serial read and write command of a certain register of the EVSE?

[bobosch]

Yes, 0 is broadcast address, in version 2.20 the load balancing option defines the modbus address (0=disabled, 1=master, 2=node 1....). will be fixed in next release.

[TonKro]

The problem is that Unit-ID 0 is not supported in Modbus...

You mean to say: [0,4,0,a0,0,1,96,10]

Unit ID = 0
Read register = 4
Address = 00 A0
Number of bytes = 1

[TonKro]

What does the unit expect with read and write command on the serial bus?

For writing one register the next works: [1,6,0,192,0,1,72,54] (decimal)
Unit ID: 1
Function (Single register): 6
Address: 00C0 (192)
Data: 01
CRC