The **S2-4AD-R** is an analog input expansion module typically used with the **LS Electric (formerly LG Industrial Systems)** XGB series programmable logic controllers (PLCs). It is designed to convert external analog signals into digital values for processing. --- ## 1. Technical Specifications Below are the primary electrical and functional specifications for the S2-4AD-R module: | Feature | Specification | | :--- | :--- | | **Input Channels** | 4 Channels | | **Analog Input Type** | Voltage and Current (Selected by wiring/switch) | | **Voltage Input Range** | 0~10V, 1~5V, 0~5V, -10~10V | | **Current Input Range** | 0~20mA, 4~20mA | | **Digital Output Resolution** | 14-bit (0 ~ 16,000) | | **Accuracy** | ±0.2% or less (at full scale) | | **Conversion Speed** | 1ms / channel | | **Isolation Method** | Photo-coupler isolation between input terminals and PLC power | --- ## 2. Key Electronic Components & Interface The module operates using several critical electronic subsystems: ### A. Analog-to-Digital Converter (ADC) The heart of the module is a high-resolution ADC. It samples the continuous voltage or current signal and converts it into a binary number (up to 16,000 points). ### B. Input Signal Conditioning * **Precision Resistors:** When configured for current (4-20mA), the module utilizes internal precision shunt resistors to convert current into a measurable voltage. * **Operational Amplifiers (Op-Amps):** These scale and buffer the incoming signal to ensure it matches the ADC's input range and to provide high input impedance. ### C. Electrical Isolation * **Photo-couplers:** To protect the main PLC CPU from high-voltage surges or electrical noise on the field side, the analog inputs are galvanically isolated from the internal logic via optoisolators. ### D. Terminal Block Interface The module features a removable terminal block for wiring. Common connections include: * **VI (Voltage Input):** For 0-10V signals. * **II (Current Input):** For 4-20mA signals. * **COM:** Common ground for the signals. --- ## 3. Configuration & Logic The "R" suffix in the model name usually indicates specific compatibility or a revision within the S2 series. To use this module, the electronic parameters must be set in the PLC software (XG5000): 1. **I/O Parameter Setting:** Define the range for each channel (e.g., 4-20mA). 2. **Filter Constant:** Electronic noise can be filtered by setting a digital filter value in the buffer memory. 3. **Data Type:** Digital values can be expressed as signed integers, unsigned integers, or percentages (0-1000).