Ametek XPF Serie Manual Del Usuario página 33

Routine calibration is carried out without opening the instrument. Allow a 5 minutes warm-up
before commencing calibration.
Equipment Required
A 5½ digit multimeter with better than 0.05% accuracy on dc Volts and better than 0.12% accuracy
on dc current to 10 Amps; alternatively use a precision shunt for current measurement.
Rheostat or other high power load arrangement to provide up to full load.
Calibration Procedure
Calibration mode is entered by holding down the three Range keys (60V/20A, 60V/7A and
20V/20A) while the POWER switch is turned on (
lamps will be lit, as a display test. When the Range keys are released the display will show the
first calibration step and the 20V/20A lamp will blink slowly. Note that when one output is in put
into calibration mode the other will briefly show Fail 4 to show that it too is 'uncalibrated' whilst
the calibration procedure is in use and cannot be used; its OUTPUT lamp will also flash.
In calibration mode the 60V/7A key steps forward to the next adjustment and 60V/20A key steps
backwards. At each step the calibration must first be made 'active' by pressing the 20V/20A key;
the 20V/20A lamp blinks rapidly when calibration is active and the calibration value is adjusted
using the MAIN and FINE VOLTAGE controls. If the 20V/20A key is not pressed at any step,
calibration is not activated at that step and the existing calibration value is retained when the step
is exited.
During calibration the top (V) display shows the calibration value and the lower (A) display shows
the step number. Some calibration values are 5-digit, in which case the 5
left- hand digit of the lower (A) display.
Some steps adjust values on the display and some adjust the output. When a step adjusts the
output, measured by the DMM, the top (V) display shows a number (the calibration count).
Calibration must be done in sequence. However, it is possible to pass through a step, without
making an adjustment, providing the 20V/20A key is not pressed, see above.
The full procedure is detailed in the table. Note the following:
•
The OVP step (step 5) will jitter because the display shows more resolution than is
available for this function.
•
The CURRENT control must be at minimum for step 6.
•
The
change load
current range must be selected on the DMM.
•
The final step in the sequence (step 11) shows
seconds stores the new calibration values and reboots the instrument in the normal
operating mode. Until this is done the new values are not stored permanently.
•
Turning POWER off at any point will retain all the old calibration values.
32
l
message between steps 8 and 9 is the point at which the high
). All the display segments and other indicator
End . Pressing the 20V/20A key for 2½
Calibration
th
digit is shown in the
(Table next page)