I've just started working with Advanced HMI today and have made some progress then ran into this issue. I have device I'm communicating with using the Modbus RTU driver. It's not a PLC but a custom controller supporting Modbus RTU over RS-485. For one function I need to write an unsigned value of 65280 to holding register 40101. I've tested this in Modbus Poll without any issues. I setup a basic label with the register 40101 to allow me to write any value I choose. When I run the panel and attempt to write this value 65280 or 0xFF00 I get an error reporting an overflow from the basic label. It seems I can write any signed 16bit value to this register but not an unsigned. I'm hoping I'm just missing something in setting up the register or value. Any help is greatly appreciated!