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General description of the
used KEITHLEY 740
for sale.
The Keithley 740 Programmable Thermometer has a built-in reference junction and will linearize any of seven different thermocouple types. Each input can be selected for any of J, K, T, E, R, S, or B type thermocouples, orforvoltage readback up to 100 mV with 1 uV sensitivity, Any input can also be turned off, allowing the instrument to skip that channel in the scan sequences. Open thermocouple conditions are detected and displayed. A single input can be read at programmable intervals to monitor temperature trends. Rates up to 20 readings/second are available for determining rapid temperature variations, and the data can be stored in the internal memory, Data can also be transferred to a computer file over the built-in IEEE-488 bus, Locate hot spots and examine time-dependent thermal characteristics, Scan intervals are programmable, and the maximum rate of 20 readings/second assures a minimum of time skew between input samples for monitoring temperature changes. A 7402 thermocouple scanner card will add nine channels of thermocouple input. Specifications. Thermocouple temperature measurement: -200° to +1821° C (Thermocouple Dependent). Maximum allowable input: 250V rms, 350V peak (for one minute). Maximum common mode voltage: 200V peak to earth. Maximum thermocouple loop resistance: 1 kohm. Filter setling time: 100 ms (typical). Scanning rate: >20 channels /second, filter disabled; >5 channels /second, filter enabled. Bench reading rate: b readings /second, filter disabled; 4 readings/second, filter enabled. Logging interval: one of 12 selectable rates from 50 ms to 1 hour, or triggered. Scanning interval: one of 10 selectable rates from 500 ms to 1 hour, or triggered. Display: Eight 0.5-inch alphanumeric LED digits with decimal point and polarity. Function, Filter, Channel, Location, Overflow, Open Thermocouple and IEEE bus status also displayed.
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