CHPA SERIES
4-4
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If XMIT SELECT is shown on the display, press the TRANSMIT/STANDBY pushbutton
until the XMIT SELECT is no longer shown. (This action will prevent the CHPA from
transitioning to the Transmit state at the conclusion of HTD.)
•
If a fault occurs during this countdown period, the FAULT LED will light and the
display will indicate the fault. (Refer to Chapter 5, “Operation,” under “Fault State.”)
3.
When HTD countdown reaches 0:00, verify that the STANDBY LED lights. Reaching this
point in the procedure indicates that the following conditions have been met:
•
Self-tests were successful.
•
The TWT (traveling wave tube) heater is warmed up.
•
No faults have occurred up to this point.
•
The CHPA is ready for the next normal step: Transmission. (Do not press the
TRANSMIT button switch at this time.)
4.5 Verifying Operational Settings
The CHPA is delivered with all of its operational values factory preset to meet the requirements
of a typical installation. Before the CHPA is used at the installation site, the user-configurable
settings must be checked and, if necessary, set to meet the user’s requirements.
4.6 Setting the Fault and Alarm Trip Points
The following Fault and Alarm Trip Point settings can be displayed and changed:
•
HELIX Over and Under voltage and current settings (Factory Authorized Access Code
required; see Appendix B.)
•
LOW RF Alarm set—A visual alarm for warning operators and for triggering an RF switch
system (refer to “RF Switch System Interface” in Chapter 3).
•
HIGH RF Alarm set—A visual alarm for warning operators.
•
LOW RF Fault set—This fault occurs if the RF output power falls below the Low RF Fault
trip point.
•
HIGH RF Fault set—This fault setting protects the CHPA against using it above the High
RF Fault trip point.
•
RF INHIBIT–A manual way to inhibit RF output. (Useful in testing.)
Use the following procedures to verify or change the trip points.
To change Helix Over and Under voltages, perform the following steps. (Before checking this
setting, read the portion of Appendix B entitled “Factory Authorized Access Code [FAAC]” —
you will find the FAAC in this section.)
