TECHNICAL NOTE – OPERATION OF MT4400 TWTA
08/10/2004
TN4400-3
MCL, INC.
9 of 36
3.2 Discrete
Control
3.2.1 AC
Breaker
The AC Breaker is used to protect internal components and to turn prime power on and off.
When the Breaker is off, all HPA control and power circuits are de-energized. Turning the
Breaker on energizes all circuits. The HPA will recover to last “On State.”
3.3
User Discrete Control & Status Interface
Discrete Control & Status Interface is supplied to allow various earth station equipment (such
as exciters) to be wired into the HPA. Refer to TN4400-2 – Technical Note, Installation Guide
for MT4400 paragraph “Discrete Interface Connections,” for a detailed signal description. The
Discrete Control & Status Interface contains the following signals:
•
WG Pressure Fault Input
•
External Interlock Fault Input
•
External RF Inhibit Input
•
Sum Fault Indicator Output
•
Sum Alarm Indicator Output
3.4
Controls & Status via Communications Protocol
The indicators and controls described in this section are provided on the HPA Remote or
Computer Terminal. Further description of these functions follows in later sections of this
document. Refer to 46A0203 and 46A0204 for a full listing of Control & Status.
3.4.1
Filament Off Command
When this command is sent from any state except Transmit, the Filament Power Supply will be
turned off.
3.4.2 Delay
State
Indicates the HPA is going through a filament warm up cycle and is not yet in Standby.
3.4.3 Standby
Command
There are two functions for this item. First, if sent while the HPA is in the Filament Off state
filament delay will be initiated. Second, if sent while the HPA is in the Transmit state the HPA
will switch to the Standby state.
