UNSOLVED Modbus: write registers

[mirage]

Hello, everyone,

I am new to the forum and need your help.
I am currently trying to get a ventilation system with Modbus connection into the ioBroker.

The reading of the values worked at first go, but now I have the problem of writing values into the system.
Unfortunately there is no separate tab in the Modbus adapter for this, but as far as I understood, you just write back into the corresponding values of the "holding" register.
When I try to do this, the adapter always crashes with the following error message:
Cannot write [257]: {"errorCode":134, "exceptionCode":1, "message": "ILLEGAL FUNCTION"}

With a Modbus tool on my Windows PC writing works without problems.

I have already collected the following contributions:
https://github.com/ioBroker/ioBroker.modbus/issues/23
Unfortunately I don't know where I could set the value "Set maxBlock to 1" to try this.

also here in the forum there was already a discussion, unfortunately without solution:
https://forum.iobroker.net/topic/26151/modbus-fc16-write-multiple-registers/4

Any help is appreciated.

Greetings,
Mirage

Systemdata	Bitte Ausfüllen
Hardwaresystem:	Synology NAS
Arbeitsspeicher:	4GB
Festplattenart:	HDD
Betriebssystem:	Linux
Nodejs-Version:	v10.19.0
NPM-Version:	6.13.4
Installationsart:	Doker
Image genutzt:	Ja
Ort/Name der Imagedatei:	buanet/iobroker:latest

adavt created this issue in ioBroker/ioBroker.modbus

closed Write holding registry doesn't work #23