Ratio; Connections - Keithley 2010 User Manual

2-20 Basic Measurements

Ratio

The Model 2010 can perform a quotient calculation between the sense input (denominator)
and the measure input (numerator). This calculation can only be performed for DC voltages.
This function can be useful when comparing several voltages to a single voltage in a piece of
equipment. The sense input is used as the reference input. With this function, the sense terminals
can be used to measure DC volts in 100mV, 1V, and 10V ranges.

Connections

Assuming factory default conditions, the basic procedure is:
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NOTE
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CAUTION
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10.
NOTE
Connect test leads to the INPUT HI and LO terminals. Either the front or rear inputs can
be used; place the INPUTS button in the appropriate position.
Connect test leads to the SENSE HI and LO terminals. Use the same inputs (front or
rear) as in the previous step.
Press DCV.
Connect SENSE LO and LO together. SENSE LO and LO cannot have a voltage
difference of greater than 5% of either lowest range selected.
Press AUTO to toggle autoranging. Notice the AUTO annunciator is displayed with
autoranging. If you want manual ranging, use the RANGE L and M keys to select a
measurement range consistent with the expected voltages.
Press SHIFT then RATIO. Use the L, M,
SENSEIN to OFF. The display will read RA for RATIO.
RATIO takes priority if both RATIO and SENSE IN are toggled to ON, and the display
will read RS at the far right. If only SENSE IN is turned ON, the Model 2010 reads
only the voltage present at the SENSE terminals.
Connect test leads from the INPUT HI and LO terminals to the source to be measured.
Connect test leads from the SENSE HI and LO terminals to the reference source.
Do not apply more than 1000V peak to the INPUT terminals or more than
350V peak to the SENSE terminals, or instrument damage may occur.
Observe the display. If the "OVERFLOW" message is displayed, select a higher range
until an on-scale reading is displayed (or press AUTO for autoranging). Use the lowest
possible range for the best resolution.
Take readings from the display.
To use autorange with the RATIO function, the following applies. When both RATIO
and SENSE IN are turned on (the display will show RS), the AUTO key applies to the
sense inputs. When RATIO is on and SENSE IN is off (display will show RA), the
AUTO key applies to the input terminals. To have autorange apply to both functions,
go into each function first and select AUTO before RATIO ON is enabled.
, and keys to toggle RATIO to ON and