Autozeroing Modes - Keithley 2182 User Manual

2-6 Voltage and Temperature Measurements
3.
Measuring internal temperature
Perform the following steps to measure the internal temperature of the Model 2182:
1.
2.
3.
4.
5.
6.
NOTE
Checking TCAL temperature
Perform the following steps to determine the internal temperature at the time of the last
ACAL:
1.
2.
3.
4.

Autozeroing modes

An A/D measurement cycle measures the input signal, and will periodically measure internal
voltages that correspond to offsets (zero) and amplifier gains, and the internal reference
temperature. These measurements help maintain stability and accuracy over time and changes
in temperature. The signal, offset, gain, and temperature measurements are then used in an
algorithm to calculate the reading of the input signal. This process is known as autozeroing.
Internally, the Model 2182 has two amplifiers that have an impact on speed, noise, drift, and
offset. These performance aspects can be controlled to some degree by controlling the available
autozeroing modes. The front-end amplifier is controlled by Front Autozero, and the second
amplifier is controlled by Autozero.
Press ENTER. The message "ACAL" will be displayed while calibration is in process.
It takes around five minutes to complete LOW-LVL ACAL and a little more than five
minutes to complete FULL ACAL. When finished, the instrument returns to the normal
display state.
Press SHIFT and then TCOUPL to display the present units designator (C, F, or K) for
temperature measurements.
To change the units designator, press the
designator, and press the
Press ENTER. The present sensor selection (TCOUPLE or INTERNL) is displayed. The
internal (INTERNL) sensor is used for measuring internal temperature.
To change the sensor selection, press the
TCOUPLE and press the
Press ENTER to return to the normal display state.
Press TEMP1 or TEMP2 to measure and display the internal temperature of the
Model 2182. Note that when displaying the internal temperature, both the "CH1" and
"CH2" annunciators are off.
As long as the INTERNL sensor is selected, TEMP1 and TEMP2 will only measure
and display the internal temperature of the Model 2182.
Press SHIFT and then CAL to access the calibration menu.
Use or key to display "CAL: TEMP".
Press ENTER. The temperature (in ˚C) at the time of the last ACAL is displayed.
Use the EXIT key to back out of the menu structure.
key to place the blinking cursor on the units
or key to display the desired units.
key to place the blinking cursor on
or key to display INTERNL.