Problem solved.
To change the I2C address of a Kmeter one need to write to register 0x08 the new address (one byte) and to register 0x09 the same address but with the bits converted (1 is 0 , 0 is 1).
After writing cycle the power.
Thanks to M5 technical help team.

Thanks.
Do you know if the firmware source is available ?

Meir.

Hi.
I need to connect 25 Kmeter Unit to one M5stack.
Is there a simple way to change the I2C address of the unit ?

Thanks.

A module or a unit with digital I/O expender that have a PNP or/and NPN interface (24 v) can be very useful .

Hi.
As I understand from your site You are pointing to the industrial IOT world .
I am using the M5Stack cores, modules and sensors for industrial machines and have sometimes a problem to install them physically because the mounting holes is for Lego (not very industrial grade) and not for normal bolts.
Also in some sensors there isn't any flat bottom that can be attached to a surface .
Maybe is time to decide if you are industrial or hobby oriented .

Meir.

@agreedk I am also using Arduino ide and not all arduino libraries works with M5stack without changes .
Did You checked the SX1509 specific library or you meant in general that Arduino libraries supposed work with M5stack ?

Thanks, Google is My almost the bast friend :-)
I am looking for a lib for M5Stack and not Arduino, the Arduino lib is not working.

Hi.
I am looking for a library for the SX1509 16 bit I/O extender.
I will be glad if someone can share.

Thanks
Meir.

Thanks, I already found a library that works with the M5core.
https://github.com/emelianov/modbus-esp8266/

Hello.
I am trying to use a M5core with LAN module to make a modbus TCP slave.
I tried a few Arduino samples but nothing works.
Can somebody help ?

Thanks