Keithley PIO-SSR-120 Multi-Channel, Parallel, Digital I/O Board

The Keithley PIO-SSR-120 is a multi-channel parallel digital I/O board that connects computers with ISA bus slots to external devices for data acquisition and control applications. It has 120 TTL/NMOS/CMOS-compatible digital I/O lines organized across five 50-pin headers, with each header supporting 24 channels. The board can directly drive solid-state relays and, when paired with external SSRs, enables control and sensing of voltages up to 280VAC and 280VDC while delivering 4000Vrms isolation. ## Technical Specifications • Digital I/O Lines: 120 channels • Signal Compatibility: TTL/NMOS/CMOS • Sink Current: 24 mA per line • Source Current: -15 mA per line • Output Connections: Five 50-pin headers (24 channels per header) • Isolation (with external SSRs): 4000Vrms • Maximum Voltage (with external SSRs): 280VAC, 280VDC • Power Consumption: +5VDC @ 1.6A typical • Operating Temperature: 0 to 50°C • Storage Temperature: 0 to 70°C • Humidity: 0 to 90% non-condensing • Physical Form Factor: ISA half-slot (5in × 4.25in × 0.75in) • Weight: 4oz ## Key Features • Interrupt-capable architecture for event-driven applications • Direct SSR drive capability for high-power switching without intermediate relay logic • Isolation rated to 4000Vrms when used with external solid-state relays • Parallel I/O configuration for high-throughput digital signal management • Low power draw from host ISA bus ## Typical Applications • Industrial automation control and monitoring • Laboratory research requiring multi-channel digital I/O • Automated test equipment and ATE systems • High-voltage load switching and sensing • Data acquisition systems requiring isolated digital channels ## Compatibility & Integration • Bus Interface: ISA • Operating Systems: MS-DOS, Windows 95/98 • Bundled Software: ExceLINX, VisualSCOPE, TestPoint, LabVIEW drivers • Power Rails: +5V, ±12V, -5V available from ISA connector