@seb There is a bug in the HW description of the M10x. Please download this file0_1495698539968_UniPiTechnology.Neuron_M10x.1.hw rename it to UniPiTechnology.Neuron_M10x.1.hw and replace it with the one in your instalation sub-folder \HwLibrary\PlatformIO (eg. C:\Program Files (x86)\Mervis\IDE 2.0.10 (52674)\HwLibrary\PlatformIO)
Then restart the IDE, delete the M10x from the TCP Modbus Channel and add it again, it should work well.
Sorry for the inconveniences.