Comtech EF Data HPCST-5000 - Manual (Page 67)

High-Power TWTA Satellite Terminals Single Thread System Installation
Rev.1 2–21
2.3.4.1.2 Digital Status Circuits
The digital status interface circuits are isolated outputs that require an internal +15 VDC
supply or an external supply to bias the digital status indicator circuits. This is
accomplished in the same manner as the control inputs by either connecting pin Y to pin
E, or applying an external supply to pin Y.
The term “Active = low” is used in the following paragraphs to indicate when a
condition is true and the status indicator is active (e.g., the photo-diode is conducting).
Except for Control/Status Return, all circuits have a maximum open voltage of 20V, and
maximum switched current is 3 mA. Switches are isolated photo-couplers.
•
Helix/Arc Fault Latched (Pin A). (Active = low.)
When active, indicates there is a helix/arc fault within the amplifier when
Pin A (+) is connected by open collector to ground (Pin W). After three
successive helix/arc faults, the automatic cycle is terminated and this line is
active (low).
•
Helix/Arc Fault (Pin C). (Active = low.)
When active, indicates there is a helix/arc fault within the amplifier when
Pin C (+) is connected by open collector to ground (Pin W).
Note: The amplifier will try to reset itself in the event of a helix/arc fault. This
line will “flash” during each reset cycle.
•
Heater Timer Complete (Pin G). (Active = low.)
When active, indicates the heater delay is in progress when Pin G (+) is
connected to by open collector to ground (Pin W).
•
TWT Temperature Fault (Pin H). (Active = low.)
When active, indicates there is a TWT Temperature fault within the amplifier
when Pin H (+) is connected by open collector to ground (Pin W). This is not a
latched fault. The amplifier automatically powers on once the TWT has cooled
to an acceptable temperature.
A TWT Temperature fault may occur from a number of causes:
! Air intake filter clogged
! Cooling fins clogged
! Fan failure
! Fan power supply failure
•
High Voltage ON (Pin K). (Active = low.)
When active, indicates that the amplifier is on when Pin K (+) is connected by
open collector to ground (Pin W).