-15-
BELFORT
INSTRUMENT
Proprietary Information
4.
Power on the Belfort AWOS HHDU. The word “ALERT” should be displayed across the
HHDU runway display. Push the “PAGE” button and the message “Belfort AWOS being
serviced” must appear. For the VHF output and the Phone output, the affected instrument
will be reported as “inoperable”. On the Advisor Screen, the indicated Alert will be reported
on the front page of the display.
5.
The Alert messages are programmed in the same order as they appear in Table 1. If an alert
message other than message 6. is displayed, consult the list of alert messages in Table 1. You
will need to toggle the tower switch an appropriate number of times until the “Belfort AWOS
being serviced” alert message is displayed. For example, if the alert message number 2 is
displayed, toggle the switch 4 times.
6.
Check and clear the altimeter pressure ports of any blockage or insect infestation. If blockage
is found, slide a wooden tongue depressor between the plates to clear the debris. Visually
check the tubes from the pressure ports to the tower, look for any indications of crimping or
degradation. Replace if necessary.
7.
Verify accuracy of pressure sensor data - Place the portable pressure standard on the ladder
at the same height (± 6 inches) as the DCP. Turn the standard on and allow it to stabilize for
five (5) minutes. Check for low battery indication (a decimal point will appear between each
digit of the displayed pressure when the battery is low).
8.
If the system has a visibility sensor, there will be a serial RS232 cable from the visibility
sensor connected to another RS232 cable which is connected to the back of the DCP.
Disconnect these two RS232 cables. Connect the cable connected to the DCP to the test
notebook computer RS232 serial communication port. If there is no visibility sensor
installed, connect the portable notebook computer (with ACBSTXCOM installed) to the
DCP through the serial communication cable that extends to the bottom of the tower.
9.
If the system has a battery backup, turn off the DC circuit breaker so battery backup is
disabled. Start the ACBSTXCOM program. After 10 seconds, turn the AC circuit breaker
in the Belfort AWOS power box off and then on again to force a reset. Immediately type
“m” <enter> to put the DCP in monitor mode. Enter the password.
10.
Type “T10” <enter> to display the measured pressure from the 2 sensors. If the measured
pressure of either of the sensors differs from the standard by more than 0.05 in Hg, it indicates
that the sensor is not suitable for calibration. The DCP must be replaced before continuing
further with this procedure. DO NOT ATTEMPT TO CALIBRATE A PRESSURE
SENSOR THAT DIFFERS FROM THE STANDARD BY MORE THAN 0.05 in Hg.
Follow the Belfort AWOS System Component Failure Instructions in Section 5.10.
11.
If either sensor differs from the standard by more than .02 in Hg, or the sensors differ from
each other by more than .02 in Hg, review the previous year’s maintenance log for the Belfort
AWOS Comprehensive Facility Performance and Adjustment Record and any Annual
Configuration Validation Performance and Maintenance Records. If the Annual Drift value
is greater than +-.02 in Hg then the sensors are suspected to be faulty and the DCP needs to
be returned to Belfort for Factory Service. If the Annual Drift value is less than +- .02 inHg,
the sensors can be adjusted. Document the Drift Value on the appropriate test record sheet.
12.
To adjust the sensors, unbolt the DCP from the tower allowing access to the tube connectors
on the back of the DCP. Remove the tubes from the back of the DCP and blow through
tubes, checking for any obstructions. After assuring the tubes are clear and reconnecting
them to the DCP (either tube to either connector is OK), start the pressure sensor calibration
process by typing “U P ~” and press <enter>. The DCP will prompt you for a password.
Summary of Contents for AWOS
Page 17: ... 14 BELFORT INSTRUMENT Proprietary Information Figure 2a Securing the Tower for Maintenance ...
Page 49: ... 46 BELFORT INSTRUMENT Proprietary Information Figure 9 Temperature Humidity Sensor Removal ...
Page 51: ... 48 BELFORT INSTRUMENT Proprietary Information Figure 10 Visibility Sensor Removal ...
Page 60: ...BELFORT INSTRUMENT Proprietary Information Appendix A Belfort AWOS Maintenance Forms ...
Page 66: ...BELFORT INSTRUMENT Proprietary Information This page intentionally left blank ...
Page 74: ...BELFORT INSTRUMENT Proprietary Information Appendix C UHF Transceiver Specifications ...
Page 88: ...BELFORT INSTRUMENT Proprietary Information Appendix F DCP Site Configuration Procedure ...