SDCS-IOE-2C is not an ordinary connection unit; it is a dedicated analog signal connection terminal unit for ABB Advant OCS/AC800M systems, commonly referred to in the industry as a signal adapter base.

It processes only signals from external field sensors or instruments; it is not responsible for power-stage measurements—such as grid voltage, armature current, or field current—within the thyristor main circuit.

The SDCS-IOE-2C is a compact plug-in card designed to slot directly into the drive control unit, eliminating the need for additional DIN-rail mounting. It features onboard RS485 communication supporting Modbus RTU data transmission to a host system, independent status indicators for each AI/AO/DI channel, and hardware-level fault detection (short-circuit and open-circuit) with fault codes reported to the drive's main controller.

It is rated for standard operating temperatures of -20°C to +70°C; the "C" designation indicates a conformal coating that provides protection against moisture, corrosion, and dust.

Measurement boards of this type fall into two main categories:

External process measurement I/O boards (IOE series: SDCS-IOE-2/2C)

Power main circuit measurement boards (PIN series: SDCS-PIN-21/22/25/4/51, etc.)

And an auxiliary measurement adapter board: SDCS-SUB-4 (low-voltage grid measurement calibration board)