TECHNICAL NOTE – OPERATION OF MT4400 TWTA
08/10/2004
TN4400-3
MCL, INC.
16 of 36
4.3
RF On/Off Control
The RF On and RF Off modes are mutually exclusive.
4.3.1
RF Off State
While the HPA is in the RF Off mode, the SSA module RF switch will be in the RF Off state.
Any of the following sources may cause an RF Off state and override all other RF On controls.
Each source will be latched and must be returned to the RF On state to clear the RF Off state.
•
Remote Interface
•
Computer Interface
•
Switchover Interface
•
User Interface
•
Tube Overdrive Fault
4.3.2
RF On State
While the HPA is in the RF On mode, the SSA module RF switch will be in the RF On state.
All of the above control sources must be in the RF On state to allow the HPA to enter RF On.
After the HPA goes into RF On the RF Low Alarm will be delayed for two seconds.
4.4
Faults & Alarms
There are two types of warning status signals produced by the MT4400. An alarm WILL NOT
affect the operating state of the HPA. A fault will shut down the high voltage power supply of
the HPA.
4.4.1 Summary
Alarm
Alarms WILL NOT affect the operating state of the HPA. All alarms are self clearing and do
not require a Fault Reset, except RF Switch Failed alarm, which will latch until the Reset
button is pressed. All alarms that will be combined to generate the Summary Alarm are listed
in the table below. While any alarm condition is present:
•
the Summary Alarm LED located on the local panel will illuminate,
•
a Summary Alarm will be indicated on the User Interface (J5), and
•
the display will present the name of the alarm on the screen (press Accept button
to clear).
ALARMS
Summary
Tube Temperature
P.S. Temperature
Filament Foldback
HPA Overdrive*
Tube Overdrive*
RF Reflected
RF Low
RF High
*
Function available with optional SSA.
