Samsung SSAS21-RTD Resistance Temperature Detector Input Module
Samsung SSAS21-RTD Resistance Temperature Detector Input Module is a high-precision thermal measurement interface designed for the Samsung SSAS21 programmable logic controller (PLC) system. Engineered for multi-channel process monitoring, it directly converts low-resistance signals from field RTD sensors into digital temperature data for real-time CPU processing without requiring external signal converters.
Technical Parameter List
| Parameter | Specification |
| Model Code | SSAS21-RTD |
| Series | Samsung SSAS21 Automation Platform |
| Supported Sensors | Pt100, Pt1000, Cu50, Cu100 (2-wire, 3-wire, 4-wire) |
| Input Channels | 4 / 8 Channels per Module |
| Temperature Range | -200°C to +850°C (Pt100 dependent) |
| Conversion Resolution | 16-bit Sigma-Delta ADC |
| Measurement Accuracy | ±0.1% of Full Scale (±0.2°C at 25°C ambient) |
| Isolation Rating | Photocoupler Isolation (1500V AC between channel and backplane) |
| Conversion Speed | 20 ms to 100 ms per channel (configurable) |
| Internal Power Draw | Powered via SSAS21 backplane 5V DC bus |
Core Advantages & Product Features
Direct Sensor Connection: Accepts 2. 3. and 4-wire RTD wiring directly, eliminating the need for costly external temperature transmitters.
Lead Wire Resistance Compensation: 3-wire and 4-wire support automatically cancels out line resistance variations over long field cable distances.
High-Precision 16-bit ADC: Delivers high thermal resolution necessary for tight temperature control loops in critical manufacturing processes.
Built-in Channel Isolation: Optoelectronic barriers protect backplane logic from high-voltage field spikes, ground loops, and electrical noise.
Wire-Break & Burnout Diagnostics: Instantly detects broken sensor wires or short circuits, sending automatic error flags to the PLC CPU.
Model Classification
SSAS21-RTD: RTD Resistance Temperature Measurement Input Module.
SSAS21-TC: Thermocouple Temperature Input Module (Millivolt sensor interface).
SSAS21-AI: Standard Analog Input Module (4–20 mA / 0–10 V DC signals).
SSAS21-AO: Standard Analog Output Module (Proportional valve and drive commands).
SSAS21-CPU: Central Processing Unit Module.
Environmental Tolerance Conditions
Operating Temperature: 0°C to +55°C (32°F to 131°F)
Storage Temperature: -25°C to +70°C (-13°F to 158°F)
Operating Relative Humidity: 5% to 95% RH (Non-condensing)
Vibration Immunity: Conforms to IEC 60068-2-6 (10–57 Hz @ 0.075 mm; 57–150 Hz @ 1.0g)
Shock Immunity: 15g peak acceleration, 11 ms duration
Enclosure Protection: IP20 (Requires mounting inside an IP54 or higher control enclosure)
Installation Method
Safety Isolation: Power down the SSAS21 base chassis before installing or removing modules.
Rack Insertion: Align the guide rails on the SSAS21-RTD module with the open chassis slot. Push firmly until the backplane multi-pin connector fully seats.
Module Locking: Tighten the upper and lower panel retention screws to secure the module against cabinet vibration.
Sensor Wiring: Wire RTD sensor leads according to the terminal pinout (3-wire setup: connect A, B, and b terminals). Use twisted-shielded copper wire.
Operating Instructions
Sensor Type Selection: Configure the target RTD type (Pt100 vs Pt1000) and wiring format (3-wire/4-wire) in the SSAS21 PLC programming software before running logic.
Shielding Practice: Ground the overall cable shield braid at the panel enclosure earth ground only to prevent ground potential loops.
Thermal Stabilization: Allow the module to run for 15 minutes after initial power-on to reach internal thermal equilibrium for optimal measurement accuracy.