Hello everyone,
I’m working on a project using a WAGO 750-8208 PLC and reading data from multiple Modbus slave energy meters over Modbus RTU (serial). I’m using the Modbus Configurator Tool to set up communication, and I’ve auto-generated the code for 5 Modbus slave devices.
Here’s the issue I’m facing:
- I initially configured one energy meter with Slave ID 4, and it worked fine — communication and data reading were okay.
- I then changed the Slave ID of the same meter to 5, updated the program, and downloaded it again.
- Now, I’m unexpectedly seeing data appear under both slave ID 4 and slave ID 5, even though only one meter (with slave ID 5) is physically connected to the serial bus.
- Strangely, in the slave ID 4 section, I see a timeout error, but the data values still change — and they match the values from slave ID 5, where there is no error and communication seems normal.
- I’ve also tried changing the array ranges from the default
1..20to200..240and40..60, but the issue still persists. - I’ve verified that the Modbus Configurator tool is generating new code correctly after each change.
It seems like some ghost values or memory references might still be lingering for slave ID 4, even after changing the configuration.
I’ve attached an image showing the issue for better understanding.
Has anyone run into a similar problem before? Any ideas on how to properly clear or isolate the old configuration to avoid this?
