The Walchem WDS620HSSNM-FN controller is now obsolete and is replaced by the Intuition-6 series of controllers. The new series is enhanced, but has similar specs. For reference, here are the specifications of the old model:
Series: WDS600
Relays/Wiring: 100-240 VAC, 2 Opto and 4 Dry Relays, Hardwired
Input Cards: Two Sensor Input Cards
Analog Outputs: No Analog Outputs
Ethernet: Ethernet Card with Modbus TCP & BACnet
Sensors: Single Disinfection Membrane-Style Flow Cell with Cable (sensors sold separately)