The Keithley PDISO-8 is an 8-channel isolated digital I/O board for control and sensing applications requiring galvanic isolation and ground-loop prevention. It combines 8 electromechanical relay outputs with 8 optically isolated inputs, interfacing through an ISA-bus compatible architecture and 37-pin D-type connector. Designed for industrial automation, process control, and laboratory environments demanding reliable signal integrity.
## Technical Specifications
**Relay Outputs**
• 8 channels: 5 Form C (SPDT) contacts, 3 Form A (SPST) contacts
• Contact rating: 3 A @ 125 Vrms (resistive load)
• Contact resistance: 100 mΩ max (initial)
• Operating time: 20 ms max; Release time: 10 ms max
• Mechanical life: 10⁷ operations minimum
• Electrical life: 10⁵ operations minimum @ full load
• Power-on state: De-energized (relays resting on NC contact)
**Digital Inputs**
• 8 channels, non-polarized optically isolated
• Input range: 5–24 VDC or VAC (50–1,000 Hz)
• Input resistance: 470 Ω to 1.6 kΩ
• Response time: 5 V minimum; Input low level: <2.5 V maximum
• Mixed AC/DC input capability
**Power & Environmental**
• +5 V supply: 0.4 A (all relays off), 1.0 A (all relays on)
• Operating temperature: 0 to +50 °C
• Storage temperature: –20 to +70 °C
• Humidity: 0 to 90% non-condensing
• Dimensions: 6.0 in × 4.25 in × 1.1 in (152 mm × 108 mm × 28 mm)
• Weight: 213 g
## Key Features
• Functional isolation prevents ground-loop faults and cross-talk
• Dry relay contacts rated for both AC and DC switching
• Channel-by-channel software filter control for noise rejection
• Accepts mixed voltage supplies (AC and DC simultaneously)
• Standard ISA-bus interface; backward compatible with legacy systems
• Optional screw-terminal connector available (STC-37)
## Typical Applications
Industrial automation, distributed process control, data acquisition systems with isolated switching, laboratory test benches, equipment monitoring and protection circuits.
## Compatibility & Integration
ISA-bus compatible PC interface; 32-bit DriverLINX drivers. Bundled with ExceLINX, VisualSCOPE, and LabVIEW support. Requires Windows 95/98/NT environment (Pentium-series processor recommended).
