8842A
Instruction Manual
5.The calibration procedure is now completed. Exit the calibration mode by pressing the CAL ENABLE switch, and attach a calibration certification sticker over the CAL ENABLE switch.
6-15. Advanced Features and Special Considerations
Table
STEP
DISPLAYED PROMPT1,2
A | 100.0 mV AC | |
B | 1.000 V AC | |
C | 10.00 V AC | |
D | 100.0 V AC | |
E | 200.0 V AC | |
1.The display also indicates “U” to show that HF AC cal is selected.
2.Inputs should be between 90 kHz and 100 kHz. (nominal) is recommended.
The 8842A has several advanced calibration features which are not necessary for the basic calibration procedure, but which can make calibration easier. The following paragraphs describe these features and also discuss special considerations for optimizing the performance of the 8842A in special situations.
6-16. STORING VARIABLE INPUTS
As a convenience, the VAR IN (variable input) feature lets you calibrate the 8842A using reference source values which differ from the values prompted by the 8842A. For example, you may want to calibrate the 200Ω range using a reference resistor with a precisely known value of 99.875Ω, rather than 100Ω as prompted. This feature is not available during A/D Calibration.
To use the variable input feature, proceed as follows:
1.When the 8842A prompts you for an input, press the VAR IN button. The blank
digits will be replaced with zeroes. You can then increment each digit of the display by pressing the range buttons. The 20Ω/mV button toggles the displayed sign.
2.Change the displayed prompt to correspond to the desired reference source by pressing the appropriate range buttons.
3.Connect the desired reference source to the appropriate input terminals of the 8842A.
4.Press the STORE button.
To meet the specifications over all ranges, the reference source for the high prompts must be between half and full scale. (The high prompts are those prompts that are between 50% and 100% of full scale.) The reference source for the low prompts must be equal to or greater than the prompted value, but not more than that value plus 4000 counts. (The low prompts are those prompts that are zero or 5% of full scale.)
For special applications, the 8842A can be calibrated at values outside the recommended range. This can enhance the performance at the calibration value. However, performance at other values may be degraded.
