After the successful connection issue yesterday,
I have successfully read/write registers in the T3 controller both with TCP and RS485.
The final step is to assign the MODBUS ID to something other than 255. For example, 3.
When connected by ethernet, I go in and select the “Main RS485” serial port and set the com port on the laptop (COM3 in this case) and the speed to 19200. Save and reboot the T3.
Using either the MODBUS Tool or another Modbus test program on a second computer, I can only read registers if the MODBUS Slave address is 255.
Most maddening is that I can read T3 register 0006 and it confirms that the MODBUS Slave address is 3. Also T3 register 0019 shows that UART2 is set for 19200. I have tried resetting , power up/down ; ethernet cable in /out, all to no avail.
I know this has to work; I’m just missing some subtle point.