The 45C231 is an analog output module designed for the Reliance AutoMate 20 series PLC system. It converts digital signals from the main CPU into standard analog output signals to drive field actuators and regulating devices. This product has been discontinued, and only refurbished, surplus or NOS units are available for maintenance and replacement of legacy industrial automation systems.

45C: Unified prefix for Reliance AutoMate 45C series control and I/O components. 231: Designates a multi-channel analog output module for AutoMate 20 platforms. No revision letter means it is the original standard hardware version.

Output Channels: 4 isolated analog output channels. Signal Type: Standard 4-20mA current signal and 0-10V voltage signal, selectable per channel. Resolution: 12-bit digital-to-analog conversion. Accuracy: ±0.2% full scale under rated operating conditions. Power Supply: 5 VDC supplied from the system backplane. Isolation: 2500 Vrms isolation between each channel and the backplane. Operating Temperature: 0°C to 55°C; humidity 20%–90% non-condensing. Mounting: DIN-rail or panel mount compatible with AutoMate 20 series backplane. Weight: Approximately 0.85 kg with rugged metal enclosure.

Field Output Terminals: Removable terminal block for connecting analog loads and actuators. Backplane Interface: Proprietary edge connector for power supply and digital data exchange with the host CPU. Status LEDs: PWR indicates backplane power status, RUN shows normal operation, and channel LEDs display output working state. Configuration: Onboard DIP switches for selecting output signal type for each channel.

It converts digital control data into standard analog signals to control valves, inverters and other field equipment. Each channel supports independent signal type selection to adapt to different field devices. Built-in isolation design effectively suppresses external interference and protects the PLC system. It conducts real-time self-check for output circuit faults and gives prompt via indicator lights. It stably transmits analog control signals to realize closed-loop process control together with the CPU.

It serves as a replacement for aging analog output modules in legacy AutoMate 20 PLC systems. It is widely used in chemical, water treatment, pharmaceutical and food industries for regulating flow, pressure and liquid level. It applies to production lines equipped with variable frequency drives, electric regulating valves and other analog-controlled equipment. It is suitable for equipment renovation projects that need to add analog output functions without replacing the whole control system.

Insert the module firmly into the backplane slot and set DIP switches to select required output signal before powering on. Connect field devices to the terminal block with shielded cables and check wiring correctness. Confirm all indicator lights work normally after powering up. Perform quarterly routine inspections to clean dust and check cable tightness. Disconnect all power and wait for complete discharge before disassembly or maintenance to prevent electric shock. Use only matched accessories and cables for long-term stable operation.