The Keithley SSIO-24 is a 24-channel solid-state I/O module accessory board that interfaces digital signals in automated test and measurement systems. It provides high-speed switching with 4000V rms isolation, enabling precise control and monitoring of AC and DC loads across industrial automation, data logging, and system test applications. The board accommodates four color-coded module types—DC input, DC output, AC input, and AC output—each optimized for specific voltage and current ranges. A 37-position D-Sub connector integrates with host test systems, while onboard LEDs provide real-time I/O status indication.
## Technical Specifications
• **Model:** SSIO-24
• **Channels:** 24
• **Termination:** Screw-in terminal blocks accepting 22–12 AWG wire
• **Interface Connector:** 37-position D-Sub
• **Dimensions:** 16″ × 4.25″
• **Isolation Voltage:** 4000V rms
## I/O Module Options
**DC Input (White)** — Senses AC or DC voltage, outputs 0 or +5V logic signal
**DC Output (Red)**
• SM-ODC5: 3–60V DC, 3.0A max load current
• SM-ODC5A: 3–250V DC, 1.0A max load current
• Response time: 100 µs (on), 750 µs (off)
**AC Input (Yellow)**
• SM-IAC5: 90–140V AC/DC input
• SM-IAC5A: 180–280V AC/DC input
**AC Output (Black)**
• SM-OAC5: 12–140V AC, 3.5A max load current (SM-OAC5R variant for reactive loads, power factor ≤ 0.5)
• SM-OAC5A: 24–280V AC, 3.5A max load current
• Response time: 0.5 cycle (on/off)
## Key Features
• Miniature solid-state relay modules eliminate mechanical switching wear
• Color-coded module types simplify field identification and replacement
• Modular architecture supports mixed-mode I/O configurations
• LED status indication for each channel
• Operating temperature range: –30°C to +80°C
• Storage temperature range: –40°C to +100°C
• Complies with EN61010-1/IEC 1010 and EU Directive 89/336/EEC
## Power Requirements
External power supply required. Current consumption: 180 mA max./115 mA typical (no modules installed); 610 mA max./270 mA typical (with modules installed).
## Typical Applications
Industrial control systems, automated test equipment, sensor-based data acquisition, switchable load management, and system validation in manufacturing environments.
