Keithley 197
The Keithley 197 is a 5½-digit, 220,000-count LCD auto-ranging digital multimeter marketed as a "Microvolt DMM" because it has 1 μV display resolution in the 200 mV range. It has basic logging capabilities and optional GPIB.
Compared to the earlier Keithley 177 Microvolt DMM, it lacks the 20 mV/20 μA/20 Ω range but has one more digit resolution.
Key Specifications
| DC Voltage | 200 mV to 1000 V FS in decade ranges, 1 μV to 10 mV LSD |
|---|---|
| DC Current | 200 μA to 10 A FS in decade ranges, 1 nA to 100 μA LSD |
| AC Voltage | 200 mV to 750 V FS in decade ranges, True RMS |
| AC Current | 200 μA to 10 A FS in decade ranges, True RMS |
| Resistance | 200 Ω to 200 MΩ FS in decade ranges, 1 mΩ to 10 kΩ LSD, diode test in 2 kΩ and 200 kΩ ranges |
| Options |
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Links
- Keithley 197 OLED display board / Bluetooth interface project thread @ EEVblog Forum / Project page @ Github / Video #1 / Video #2 (Graph)
- Reverse engineering of the internal IEEE interface of the Keithley 197A @ EEVblog Forum
- Keithley 197 teardown and repair (Kerry D. Wong)
Internals
The GPIB interface communicates with the base instrument over an opto-isolated serial port. It uses a separate MC146805 CPU.
Pictures
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