Omron C120-0C222 I/O Module 3G2A6-0C222

The Omron C120-0C222 (alternative part number 3G2A6-0C222) is a mixed input/output module designed for the Omron C120 series programmable logic controller. This unit provides 16 digital inputs and 16 transistor outputs, occupying a single slot in the C120 base rack. It is also compatible with C20K and C28K base units, making it suitable for legacy system maintenance and expansion.

Input Specifications

The 16 input points are arranged into two groups of 8, each group sharing a common return (COM). Input type: 24V DC sink/source (factory default sink). Input voltage range: 20.4–26.4 VDC. Input current: 7 mA typical at 24V. ON voltage: ≥16 VDC; OFF voltage: ≤5 VDC. Response time: 8 ms (standard), but can be adjusted to 0.5 ms via a DIP switch for high-speed counting. Each input has an LED indicator (green) for status.

Output Specifications

The 16 output points are NPN open-collector transistors rated for 24V DC, 0.5 A per point (resistive load). Maximum total current per common (two groups of 8) is 4 A. Outputs are protected against short circuits (foldback current limiting at 1 A). Off-state leakage current<0.1 mA. Switching time: ON <0.5 ms, OFF <1 ms. Output LEDs (yellow) show energization. The outputs are isolated from the internal logic (1500 VAC).

Power Consumption and Isolation

The module draws 200 mA from the +5 V backplane supply and requires an external 24V DC for the output drive (max 100 mA plus load). Inputs are powered from the same external supply. Isolation between input and output circuits is 1000 VAC. The module includes built-in surge suppression for outputs (varistor).

Physical and Environmental

Dimensions: 200 mm height, 35 mm width, 102 mm depth (standard C120 module size). Weight: 300 g. Operating temperature: 0 to 55°C; storage: -20 to 75°C. Humidity: 35% to 85% non-condensing. Vibration resistance: 2 g (10–55 Hz). Connection: 30-pin connector on rear for backplane bus and front accessible screw terminals (M3.5, wire size 0.5–1.5 mm²). Terminal cover included.

Compatibility and Addressing

When installed in a C120 rack, the inputs occupy word I (e.g., IR 000–015) and outputs word O (e.g., OR 000–015), automatically assigned by the CPU based on slot position. For C20K/C28K systems, the addressing follows the same pattern. The module is not hot-swappable; the system must be powered off for installation. Compatible CPUs: C120, C120F, C20K, C28K.

Typical Applications

Used in older industrial machinery such as injection molders, printing presses, and textile looms. The 16/16 configuration is ideal for controlling small assembly stations or feeding signals from limit switches and photoelectric sensors. The fast input response (0.5 ms) allows counting of encoder pulses up to 1 kHz.

Maintenance and Spare Parts

The fuse for the external 24V supply is a 5x20 mm 3.15A fast-blow (accessible on the side). Replacement terminal block (3G2A6-TB222) is available. The module’s board is coated with anti-humidity varnish. For troubleshooting, an input simulator (3G2A6-SIM01) can be used to inject signals.

Ordering and Documentation

Part numbers: C120-0C222 or 3G2A6-0C222. The module is supplied with a dust cover and labeling sheet. Manual: Omron C120 Operation Manual (W166-E1-1). Compliance: CE, RoHS (lead-free solder).