Stanford Research SR245 – Computer Interface Module

The Stanford Research Systems SR245 Computer Interface Module bridges computers and experimental setups within the SR200 Series modular platform. It enables automated data acquisition and instrument control through dual communication interfaces, software-configurable analog I/O, and programmable digital logic. The module stores up to 3500 measurement points and operates in both synchronous and asynchronous modes for flexible laboratory integration.

– Technical Specifications

Analog I/O
• 8 channels, software-configurable as inputs, outputs, or mixed
• 13-bit resolution per channel
• ±10.24 VDC full-scale range
• 0.05% accuracy
• 1 MΩ input impedance
• ±40 VDC input protection

Digital I/O
• 2 TTL I/O bits on front panel (counter/trigger capable)
• 1 × 8-bit input port and 1 × 8-bit output port on internal connector
• TTL logic: logic one > 3 VDC, logic zero < 0.7 VDC
• ±10 VDC TTL input protection

Memory & Interfaces
• 3500-point buffer memory for measurement storage
• RS-232 serial communication
• GPIB (IEEE-488) instrument control interface
• Simple ASCII command set compatible with high-level languages

– Key Features

• Dual operational modes: synchronous (MS command) with response after trigger, and asynchronous (MA command, default) with immediate response
• Internal configuration switches for setup matching with control software (e.g., SR272)
• Direct analog voltage measurement on individual channels via simple commands
• Scan parameter control supporting single, continuous, and time-based scan configurations
• Analog output ramp control for gate scanning applications
• Digital counter value readout capability

– Typical Applications

The SR245 enables computer-automated experiments requiring synchronized data acquisition, analog signal measurement and generation, and digital event counting. It serves as the control interface for gated integrator and fast sampler modules within experimental workflows.

– Compatibility & Integration

The SR245 integrates directly into the SRS SR200 Series modular platform, facilitating control of companion modules such as the SR250 Gated Integrator and SR255 Fast Sampler. Configuration via internal switches ensures proper operation with associated control software.