RF Directional Thruline® Wattmeter Model APM–16
22
Calibrating
1.
Remove any dust plug or element from the APM.
2.
Allow the APM and all equipment to stabilize with respect to the workspace
environment.
Note:
The APM and the calibration element may require up to 24
hours for complete stabilization if brought from an extreme stor-
age environment.
3.
Set the APM to OFF.
4.
Turn the zero screw until the pointer rests at zero (See
Figure
1 on page
1
for screw location).
5.
Switching between BAT and OFF, rezero until a repeatable zero is obtained.
6.
Pierce the label inside the circle with an “X” in it (See
Figure
1 on page
1
to
locate the hole).
Note:
The calibration access hole is covered by a label showing
the calibration date.
Note:
Disturbing the calibration label within the one-year war-
ranty period will void the warranty.
7.
Connect the power supply, voltmeter, and calibration element as shown in
Figure
11
above.
Note:
The APM does not need to be connected at this time.
8.
Turn on the voltmeter and power supply.
9.
Set the output to 2.00 ± 0.1 V. Allow the equipment to stabilize for the time
recommended by the manufacturer, but for no less than five minutes.
10. Set the APM to ON and allow it a minimum of five minutes to stabilize.
11. After the equipment has stabilized, check the battery in the wattmeter by
momentarily setting the power switch to BAT.
12. If the pointer does not swing into the BATTERY TEST region, replace the
battery, set the switch back to ON, and allow the APM to stabilize for
another five minutes before continuing.
13. Insert the calibration element into the wattmeter.
14. Rotate it in either direction until it stops, then rotate it back 90° to short
circuit the contact to the line section body.
15. Rotate the calibration element in either direction until it stops.
16. Adjust the calibration potentiometer (through the calibration access hole)
until the pointer rests at “25” on the upper scale.
