Comtech EF Data HPCST-5000 - Manual (Page 123)

High-Power TWTA Satellite Terminals TWT Amplifiers
Rev. 1 4–5
4.1.2.5.1 Clearing Faults
Faults can be cleared in two ways:
1. Cycle High Voltage OFF, then ON.
2. Momentarily set the Fault Reset control line low.
If the fault condition occurs frequently, maintenance action is required.
4.1.3 Control and Status Signals
4.1.3.1 Control
1. AC Power ON.
Connect Pin a to Pin W (ground) to power ON the amplifier.
2. High Voltage ON/OFF.
This control signal turns the High Voltage ON (control line set low) or OFF
(control line set high). The High Voltage ON signal enables TWT amplification
by turning the TWT electron beam on or off.
3. Heater Standby.
This control signal reduces the voltage applied to the TWT heater
(ON = control line set low) (see Section 4.1.2.2 for details). Turning High
Voltage ON overrides the Heater Standby command and returns the TWT heater
voltage to normal operating value.
4. Fault Reset.
This control signal resets the High Voltage fault and Helix Current fault
(reset = control line momentarily set to low).
Note: Turning the High Voltage OFF also clears faults.