Samsung SSAS21-CPU Central Processing Unit Module
The Samsung SSAS21-CPU Central Processing Unit Module serves as the primary processing engine for Samsung’s SSAS21 industrial automation and PLC control platform. Engineered for real-time control, process automation, and high-speed data execution, the SSAS21-CPU coordinates field I/O modules, manages system communications, and executes complex logic routines in harsh industrial environments.
Product Introduction / Overview
The Samsung SSAS21-CPU is designed to deliver high-performance logic processing and system stability for automated assembly lines, manufacturing equipment, and infrastructure control systems. It features built-in self-diagnostics, multi-protocol communication support, and solid-state non-volatile memory to prevent program loss during total power outages. Its modular design allows seamless integration with SMTB series terminal boards and SSAS21 expansion racks.
Technical Table
| Specification Parameter | Value / Details |
| Model Code | SSAS21-CPU |
| Series | Samsung SSAS21 Automation Platform |
| Processor Type | 32-bit High-Speed RISC Microprocessor |
| Program Memory | Non-volatile Flash Memory / SRAM with battery backup |
| Execution Speed | Sub-microsecond per Boolean instruction |
| Max. I/O Capacity | Supports up to 2048 local/remote digital & analog points |
| Communication Ports | RS-232C, RS-485 (Modbus RTU), Fieldbus Interface |
| Operating Voltage | 24 V DC (via backplane power supply module) |
| Status Indicators | RUN, ERROR, ALARM, BATTERY, COM LEDs |
| Mounting | SSAS21 Series Dedicated Rack / Backplane Chassis |
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)
Relative Humidity: 10% to 95% RH (Non-condensing)
Vibration Immunity: 10 to 57 Hz @ 0.075 mm amplitude; 57 to 150 Hz @ 1.0 g acceleration
Noise Immunity: Noise voltage 1500 Vp-p, pulse width 1 µs via noise simulator
Enclosure Protection: IP20 (Requires mounting inside an IP54-rated industrial cabinet)
Operating Instructions
Pre-Power Inspection: Ensure the CPU module is firmly seated into Slot 0 of the SSAS21 backplane chassis and the locking mechanism is engaged.
Program Download: Connect the programming terminal to the CPU port (RS-232/RS-485) and transfer the control ladder logic/configuration.
Mode Selection: Switch the physical keyswitch/toggle on the front panel from STOP/PROGRAM to RUN mode to begin logic execution.
Battery Replacement: Replace the internal lithium backup battery while system power is ON to prevent SRAM program memory loss during planned shutdowns.
Fault Diagnosis & Troubleshooting
ERROR LED Solid Red: CPU execution halt due to critical system error (checksum error, watchdog timer timeout). Cycle power; if persistent, re-download the ladder program.
BATTERY / BATT LOW LED On: The internal memory backup battery voltage has dropped below operational thresholds. Replace with a standard Samsung lithium battery module.
COMM / TX/RX LED Off: Check communication cables, terminal resistor settings, and baud rate parameters between the CPU and host system.
I/O BUS Fault: Verify backplane connectors for bent pins or contamination; ensure all expansion modules are securely locked into the rack.
Related Models in the Same Series
SSAS21-PWR: Main Power Supply Module for SSAS21 rack chassis
SSAS21-BASE: Multi-slot Expansion Backplane Base Unit
SMTB-DI: Digital Input Terminal Board interface module
SMTB-DO: Digital Output Terminal Board interface module
SMTB-AI: Analog Input Signal Conditioning Module
SMTB-RTD: RTD/Thermocouple Temperature Input Board
Storage Conditions
Storage Temperature Range: -25°C to +70°C (-13°F to 158°F)
Humidity & Atmosphere: 5% to 95% RH non-condensing in a corrosive-gas-free environment.
Packaging Protection: Keep sealed in original moisture-barrier ESD safe bags with desiccant until final installation.