Calibration - Time Electronics 9814 Technical Manual

Section 8 - Calibration
Introduction
The automatic calibration (auto-cal) feature of the 9814 enables independent calibra-
tion of the zero, positive and negative outputs of all DC ranges either from the front
panel or via the IEEE bus. The calibration factors are stored twice in memory and
when the 9814 is switched on the factors are compared to check for any corruption.
Should an error be found the message ERROR 6 will be displayed on the front panel.
When using auto-cal, all calibration factors may be zeroed and the operation of the
calibration memory verified by inserting the CAL key and selecting self test (i.e. all
IEEE address switches to the left and switch on). Self test can be run without insert-
ing the CAL key which leaves the calibration factors unchanged.
If the CAL key is inserted when the 9814 is not addressed for auto-cal, the display will
flash ERROR 7.
Setting the 9814 into auto-cal mode.
The 9814 is set into auto-cal mode as follows:
1. Switch off and select IEEE address 0 or 16
2. Switch on and insert CAL key. The front panel display will show a flashing C.
Recalibrating from the front panel
All ranges can be calibrated independently or in any sequence, it is necessary to set
the zero before adjusting full scales.
1. Select the range to be calibrated.
2. For ZERO calibration, (DC only) set a value on the display which makes the out-
put of the 9814 zero, then press SELECT followed by ZERO which will set the
output to zero. Press ZERO again and the display will zero.
3. For FULL SCALE calibration, set the display to full scale or to the value required
as the point to check against a standard (e.g. checking the 1V range against a
standard cell). Press DEV, adjust the output to the correct value and press DEV
again. This saves the calibration factor. The negative full scales are adjusted in
the same way
Recalibrating over the IEEE bus
1. Select the range to be calibrated.
2. Set the output to zero by setting a value to cancel the zero error then send com-
mand 'Z' to store this value.
3. Set the output to full scale and select deviation required to adjust output to cor-
rect value with command 'PX.XXX'. When another command is received the value is
saved.
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