Bird Technologies 4314C - Manual (Page 40)

28
Calibrating the Wattmeter
The 4314C requires a total of three calibrations to set zero and gain. These cali-
brations must be performed after the meter or instrumentation module has
been replaced. Additionally, a mechanical zero adjustment of the meter pointer
is done any time the pointer is not exactly aligned with the zero mark on the
meter scale when no power is being applied in CW mode.
Note: Before beginning this procedure, a DC Input element (4381-
050) is needed.
PEAK Mode Zero Adjust
To ensure that the meter reads correctly for both CW and PEAK operation:
1.
Short the input by doing one of the following:
•
Insert a dust plug
•
Position a standard element with the arrow pointing down
2. Set the CW/PEAK switch to CW mode.
3. Ensure the pointer rests at 0.
Note: If the pointer needs to be adjusted, zero the pointer by turning
the mechanical zero adjustment screw located at the bottom front
center of the meter face. See “Zero Adjust Meter” on page 9
4. Set the CW/PEAK switch to PEAK mode.
5. Attach a voltmeter to the posts on the back of the meter.
6. Set the voltmeter to read in mV scale.
7. Slowly adjust the “ZERO ADJ.” potentiometer with a small screwdriver
(Figure 11 on page 29) until the reading shown on the voltmeter is 0.0mV.
8. Ensure that the pointer rests at 0.
Note: There should be no pointer position variation between CW and
PEAK modes.
PEAK Mode Gain Adjust
1. Remove the dust plug standard element, if present.
2. Insert DC Input element (4381-050) into the line socket.
3. Apply approximately 34 mV from a DC power supply to the connector on
the DC Input element.
Note: If a non-adjustable voltage supply is being used, install a volt-
age dividing potentiometer in series.
4. If necessary, adjust the “GAIN ADJ.” potentiometer with a small screwdriver
(Figure 11 on page 29) so that the same reading is attained in both CW and
PEAK modes.