We are faced with the task of monitoring the state of two heat pumps and controlling them via Modbus RTU.
For this purpose, we purchased your two T3-LB-WIFI-1kPT controllers.
It’s assumed that the T3-LB controller will be the Modbus Master and will be connected to two heat pumps with Modbus addresses 11 and 12 via the RS-485 network.
The control logic for the two heat pumps is programmed in the T3-LB controller, which controls the pumps by writing the required values to the MODBUS HOLDING REGISTERS of the heat pumps.
I spent several days studying your forum and help for the T3000 program and here is what I managed:
to emulate the heat pump, I used the “Modbus Slave” program on my PC and entered the test data in HOLDING REGISTERS 40001-40005:
next I set up the connection in T3000:
and wrote a small program for reading and writing Modbus values:
and here is what I got in the T3000 variables:
Thus, the program reads MODBUS HOLDING REGISTERS but for some reason does not write, see HR40005.
QUESTION 1: WHY? What did I do wrong?
QUESTION 2: In heat pumps, besides MODBUS HOLDING REGISTERS (register numbers 40001-49999, r/w), MODBUS INPUT REGISTERS (register numbers 30001-39999, r) are present. How can they be read by the controller?
I ask you to respond promptly, the task is urgent.