888-2408-002 4-35
WARNING: Disconnect primary power prior to servicing.
Overall System Theory
These cal factors and A/D values will be approximately the same for all Z5
transmitters that are factory calibrated or have been field calibrated at the rated
transmitter power of 5kW as detailed in the Maintenance procedures. These
numbers are also stored in the Backup memory area of the EEPROM, U39 and can
be recalled if necessary. The actual numbers obtained during the factory calibration
are recorded in the Factory Test Data.
NOTE:
If the transmitter is calibrated at other than 5kW these numbers will change
and their new values should be recorded.
It is important to note that as long as the hardware calibration of the forward and
reflected directional couplers is not disturbed, the Cal Factors could be entered
manually and the transmitter calibration would be within a few percent of the
factory calibration. To access the edit controls for each parameter, go to the screen
containing the value and press and hold the [D] button and then press [C]. The edit
controls should now show up on the screen.
!
CAUTION:
ENTERING A WRONG VALUE IN ONE OF THESE SCREENS COULD
CAUSE SERIOUS DAMAGE TO THE TRANSMITTER OR EXTERNAL
SYSTEMS. IT IS RECOMMENDED THAT THESE NUMBERS BE RECALLED
FROM THE BACKUP MEMORY OR BE OBTAINED BY FOLLOWING THE
CALIBRATION PROCEDURES AS OUTLINED IN SECTION V,
MAINTENANCE.
The following is a description of each of theCalibration and A/D parameters.
4.7.2.1 DAC_APC_REF
DAC_APC_REF [HOME, MORE, CONFIGURATION C,B] is a counter (internal
to the micro), whose output will be between 0 and 900, that is controlled by the
RAISE and LOWER buttons on the front panel. RAISE increases the count and
LOWER decreases the count. This number is then D/A converted to get the
APC_REF voltage which controls the APC loop discussed earlier in this section.
The correct APC_REF voltage for a specific DAC_APC_REF number can be
calculated from the formula:
APC_REF voltage = DAC_APC_REF * 0.004883
Example: For the nominal DAC_APC_REF value of 660, APC_REF Voltage = 660
* 0.004883 = 3.22V and can be measured at TP8 on the Master Controller. This
DAC value is used to control transmitter power level for all conditions where the
Master Controller is operational and the APC Loop switch S1-10 is closed.
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