The Magelis HMISTU (655/855) can communicate to a Zelio Smart relay via Modbus serial or Modbus/TCP (Ethernet).
For serial communication you would need the the following.
XBTZ9980 cable 2.5m or the ZBTZ9982 10m
SR3MBU01BD Zelio Modbus module
For Ethernet communication:
Ethernet cable
SR3NET01BD Zelio Ethernet module.
Both Zelio communication modules are compatible with the SR3B***BD smart relay only.
For serial communication you would need the the following.
XBTZ9980 cable 2.5m or the ZBTZ9982 10m
SR3MBU01BD Zelio Modbus module
For Ethernet communication:
Ethernet cable
SR3NET01BD Zelio Ethernet module.
Both Zelio communication modules are compatible with the SR3B***BD smart relay only.