Small Instrumentation Modules SIM970 — 5½-digit quad digital voltmeter · True 5½-digit performance · Four isolated channels · 3 decade autoranging to ±19.9999 V · 10 MΩ input impedance · Trigger input for data synchronization · Unique continuous auto-calibration · 90 dB power line frequency rejection SIM970 Quad Digital Voltmeter The SIM970 Quad Digital Voltmeter is designed to make precision DC voltage measurements with excellent longterm accuracy. For applications in which many voltages must be monitored, up to 16 DVM channels can be put into one SIM900 mainframe. Four voltage ranges from ±199.999 mV to ±19.9999 V can be autoranged or manually selected. An external trigger input allows synchronization of voltage readings on all four channels for critical applications requiring coincidental readings. A BUSY output gives a TTL (logic high) signal when readings are being taken. The bright front-panel LED display shows updated readings three times per second. Computer access through the SIM900 mainframe (RS-232 or GPIB) permits data logging with 24 bits of resolution. All channels are isolated from ground and each other. The SIM970 uses isolated BNC connectors for inputs so coaxial cables can be used for reduced noise pickup. Auto-calibration is performed with every reading by sequentially measuring not only the input voltage, but also the ground and the full-scale voltages against a calibrated internal reference. This auto-calibration routine virtually eliminates offsets and scale errors, and ensures smooth range-torange transitions. Stanford Research Systems

Full-scale DC voltage ranges Range Voltage Resolution Noise, counts rms Wl2! Measurement accuracy, ±(% of reading + counts)131 Range 24 hour, (23 ±1)°C 90 day, (23 ± 5) °C (typ.) 1 year, (23 ± 5) °C (typ.) Transfer accuracy Input resistance Input terminals Input protection BUSY output Normal mode rejection Settling time Operating temp. Internal, external (TTL), or remote TTL logic high when busy 1 s to within 3 counts of final indication. Green LEDs for range Isolated BNC (4 front), BNC (2 rear) by user-provided power supply (+5 V) One year parts and labor on defects [1] One count is a unit change...