Section 3: Calibration
Model 2461 Calibration and Adjustment Manual
3-6
2461-905-01 Rev. A / February 2016
Step 3. Current calibration verification
Keithley Instruments recommends two different connection configurations for current calibration
verification:
For the 1 µA to 1 A ranges, use the connection diagrams in
Connections for the 1 µA to 1 A
(on page 2-5).
For the 4 A to 10 A ranges, use the connection diagrams in
Connections for the 4 A to 10 A
(on page 2-5).
The following topics describe how to do current calibration verification for each of these
configurations.
To meet digitizer accuracy specifications, digitizer autocalibration (ACAL) must be performed within
one week of verification, and the Model 2461 internal temperature must be within 5 °C of the last
ACAL temperature. See the
Model 2461 Reference Manual
for information about autocalibration.
Digitizer accuracy is specified for the average of 1000 samples at 1 µS intervals. In the interest of
simplicity, this condition is met in the procedure below by setting the digitizer aperture to AUTO and
reading a single sample at a 1000 readings/s sample rate. This returns the average of 1000 1 µS
samples automatically in a single reading. See the
Model 2461 Reference Manual
for more
information about aperture, sample rate, and different methods of acquiring digitizer measurements.
Current calibration verification for the 1 µA to 1 A ranges
Follow the steps below to verify that Model 2461 current source-measure-digitize accuracy is within
specified limits. In this test, you set the output current to each full-range value and measure the
current with a precision digital multimeter (DMM).
To calibrate the 1 µA to 1 A ranges:
1. With the source output off, connect the Model 2461 to the DMM using the connection
configuration in
Connections for the 1 µA to 1 A ranges
(on page 2-5).
Hazardous voltages may be present on all output and guard terminals. To prevent electrical
shock that could cause injury or death, never make or break connections to the Model 2461
while the instrument is powered on. Turn off the equipment from the front panel or
disconnect the main power cord from the rear of the Model 2461 before handling cables.
Putting the equipment into standby does not guarantee that the outputs are powered off if a
hardware or software fault occurs.
2. Turn on the Model 2461 source output.
If the Model 2461 is not already warmed up, allow it to warm up for at least one hour before
continuing to the next step.
