Multi-proxy modbus connection - Printable Version

Multi-proxy modbus connection - Printable Version

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Multi-proxy modbus connection - gianluca_depascali@hotmail.it - 09.09.2024

Hi everybody!

I have a problem about modbus writing.
In this work there is two airconditioning connected to modbus and it have the same modbus ID (49). I can't change it because the company don't allow it.
I connected this two device to the two different port of RS485.
But the problem is to open comunication with proxy. You can't specificate where it have to open comunication.
I use this script:

Code:
-- get value of object with group address 1/1/1

setpoint_z2 = grp.getvalue('1/1/1')

setpoint_z2_mb = setpoint_z2*2

-- proxy works only when RTU is enabled in Modbus settings

mb = require('mbproxy').new()

mb:setslave(49)

-- set register at address 6

mb:writeregisters(6, setpoint_z2_mb)

-- read from address 6

value_rmb = mb:readregisters(6)

RE: Multi-proxy modbus connection - admin - 09.09.2024

You can pass the RTU port number (1, 2 or 3) when creating a proxy connection like this:

Code:
require('mbproxy').new(2) -- use RTU 2

Make sure to configure and enable both ports in RTU settings.