Expansion Points: You can add T3E-XXX series controllers and the extra IO will show up as inputs and outputs on the associated controller. In the case of 3rd party Modbus devices, these will need to be ‘integrated’ over Modbus read & write commands. You could in fact use a control basic program to write to the external modbus registers to the on board ‘inputs’ so in fact it would have the same effect as some expansion IO but it needs the small control basic program to drive it. You can read about network programming here: https://forums.temcocontrols.com/t/network-programming-overview/316
Ethernet Devices: You can read and write to Bacnet and Modbus devices over Ethernet as well, check the same link above to learn more about that.
