The way I use it, I got an Universal Robots to control the modbus, and for that to work I need to uncomment #define TCP_KEEP_ALIVE in the ModbusIP.h file. When keep alive is commented out, the green dots are randomly blinking green/gray, but with it uncommented the connection is stable and all dots are green.
With the ENC28J60 based board, the green dots are always blinking gray/green, no matter if keep alive is uncommented or not, so I suspect it got something to do with that. But I cant figure out what is wrong, so I am looking for help from someone who understands the ENC28J60 library better than I do.
Also, testing it with the UIPEthernet library, it works, but VERY slow and unreliable.
With my Arduino Ethernet I can run all in and outputs at 10Hz, and it is replying stable at 8-9ms, with the UIPEthernet library it runs at 15-30ms, with spikes over 350ms.
Another problem I am having is also that only the first input is working correct. The others always show as activated, I suspect it to be something in the modbus protocol not being handled correct by ModbusIP.