The **FP3-R20-R** is a specific Programmable Logic Controller (PLC) CPU module from the **Panasonic (formerly Matsushita/NAIS)** FP3 series. It serves as the "brain" of the control system, managing inputs, outputs, and logic processing. --- ## 1. Technical Specifications The FP3-R20-R is designed for high-speed industrial automation tasks. Below are its core technical attributes: | Feature | Specification | | :--- | :--- | | **Series** | FP3 Series | | **Control Method** | Cyclic scan system | | **Programming Language** | Relay symbol (Ladder Diagram) / Instruction List | | **Program Capacity** | 10k to 30k steps (depending on memory card used) | | **I/O Points** | Up to 2,048 points (with expansion) | | **Execution Speed** | 0.15 $\mu$s per basic instruction | | **Power Supply** | Typically requires an FP3 Power Supply Module (e.g., FP3-PSA) | --- ## 2. Key Electronic Components & Ports The hardware architecture of the FP3-R20-R includes several critical interfaces for industrial communication: ### A. Memory Architecture * **RAM/ROM:** It utilizes internal RAM for logic execution. It usually requires a separate memory unit (RAM or EPROM) to be inserted into the front slot to store the user program. * **Battery Backup:** Contains a lithium battery (often the **AFP3801**) to retain data and programs during power loss. ### B. Communication Ports * **RS232C Port:** Located on the front for connecting to Human Machine Interfaces (HMI) or programming software (FPWIN Pro/GR). * **Tool Port:** Dedicated port for the hand-held programming console or PC link. ### C. Status LEDs The module provides diagnostic feedback through integrated LEDs: * **RUN:** Green LED indicating the CPU is executing logic. * **PROG:** Indicates the CPU is in programming mode. * **ALARM/ERROR:** Red LED indicating a system fault or battery failure. --- ## 3. System Architecture Role The FP3-R20-R is a **Modular PLC** component. To function, it must be mounted on a backplane (baseplate) alongside: 1. **Power Supply Module:** Converts AC line voltage to DC for the internal bus. 2. **I/O Modules:** Digital/Analog cards that interface with physical sensors and actuators. 3. **Intelligent Modules:** Positioning or Communication modules for specialized tasks. --- ## 4. Maintenance & "R" Designation The **"-R"** suffix in Panasonic part numbers often refers to a "Relay" type or a specific revision involving **Relay outputs** if it were an I/O module; however, for this CPU, it specifically denotes the **standard CPU model with built-in RAM/Clock functions**. > **Note:** If the "ALARM" light is flashing, the most common electronic failure is the internal backup battery, which typically lasts 3–5 years.