Comtech EF Data HPCST-5000 - Manual (Page 66)

Single Thread System Installation High-Power TWTA Satellite Terminals
2–20 Rev.1
2.3.4.1.1 Control Interfaces
There are five control inputs as follows:
•
AC Power ON (Pin a).
Connect Pin a to ground (Pin Z) to enable operation of the amplifier and turn the
TWT heater on.
C AU TIO N
The AC control circuit does not affect the connection of the power
amplifier to prime power. Disconnect Prime Power when the power
amplifier is serviced.
•
High Voltage Enable (Pin F).
Connect Pin F to ground (Pin W) to turn high voltage on.
•
Heater Standby (Pin J).
Connect Pin J to ground (Pin W) to reduce the voltage applied to the TWT
heater. This feature is provided to extend the life of the TWT when the amplifier
is the back-up unit in a redundant configuration. The High Voltage ON overrides
the Heater Standby command and returns the TWT heater voltage to normal
operating value.
•
Fault Reset (Pin X).
Momentarily connect Pin X to ground (Pin W) to reset the high voltage fault and
helix current fault.
Note: Turning the High Voltage OFF will also clear these faults.
•
AC Command Return (Pin Z).
Common return.
The external control inputs require +15 VDC pull-up. This is possible from the internal
+15 VDC of the amplifier or from an external DC supply. Both configurations are
described in the following paragraphs.
•
Using the Internal +15 VDC for Control, connect pin E to pin Y.
•
Using an External DC Supply for Control, connect pin Y to external +15V
source and source return to pin W.
Note: The EFData system harness is pre-wired to use the +15V output of the TWTA as
the input to the control pull-ups.