The **FC4A-R081** is a specific digital output expansion module belonging to the **IDEC MicroSmart FC4A series** PLC (Programmable Logic Controller). It is designed to expand the base controller's capabilities by adding relay contact outputs. --- ### ## Technical Specifications The following table summarizes the key electronic characteristics of the FC4A-R081 module: | Parameter | Specification | | :--- | :--- | | **Output Points** | 8 Points | | **Output Type** | Relay (Electromechanical) | | **Connection Type** | Removable Terminal Block (M3 screws) | | **Rated Load Voltage** | 24V DC / 240V AC | | **Maximum Load Current** | 2A per point (7A per common) | | **Mechanical Life** | 20,000,000 operations (no load) | | **Electrical Life** | 100,000 operations (at rated load) | | **Response Time** | 10ms (ON/OFF) | --- ### ### Electronic Architecture & Components #### 1. Relay Contacts (Electromechanical) Unlike transistor outputs (which are solid-state), the FC4A-R081 uses physical mechanical switches. - **Advantage:** It can handle both AC and DC voltages and provides high current capacity. - **Isolation:** Provides physical galvanic isolation between the PLC internal logic and the external load, protecting the CPU from surges. #### 2. Status Indicators (LEDs) The module features integrated diagnostic LEDs on the front panel: - **PWR (Green):** Indicates the expansion module is receiving power from the PLC bus. - **OUT (Amber):** Each of the 8 channels has an individual LED that illuminates when the internal relay coil is energized. #### 3. Power Consumption The module draws its power directly from the PLC base unit via the expansion bus connector. - **Internal Current Draw:** Approximately 40mA at 5V DC and 50mA at 24V DC (when all relays are ON). --- ### ### Wiring Configuration The outputs are typically organized into "Commons" to simplify wiring. In the FC4A-R081: - Points are usually grouped (e.g., 4 points per common). - You can mix different voltages (e.g., 24V DC on one group and 120V AC on another) as long as they share the same common terminal. --- ### ### Protection Measures When using this module with inductive loads (motors, solenoids, or contactors), electronic protection is recommended to prevent contact pitting: - **For DC Loads:** Connect a diode in parallel with the load. - **For AC Loads:** Connect an RC snubber circuit across the load.