XT-50, XT-80, and XT-100 Amplifiers
Installation
2-11
••
High Voltage Fault (Pin R)
. (Active = low) When active indicates
there is a high voltage fault within the amplifier when
Pin R
(+) is
connected by open collector to ground
(
Pin W
). Maximum open voltage is 20 volts and maximum
switched current is 3 mA. The switch is an isolated photo-coupler.
A high voltage fault is typically an indication of a serious power
supply failure.
••
Fan ON High (Pin S)
. (Active = low) When active, indicates that
the TWT has heated up to the point that the fan must run at its
manufacturer's rated voltage when
Pin S
(+) is connected by open
collector to ground (
Pin W
). Maximum open voltage is 20 volts and
maximum switched current is 3 mA. The switch is an isolated
photo-coupler.
••
Summary Fault (Pin T)
. (Active = low) When active, indicates
there is a fault within the amplifier when Pin T (+) is connected by
open collector to ground (Pin W). Maximum open voltage is 20
volts and maximum switched current is 3 mA. The switch is an
isolated photo-coupler.
••
Fan Lock (Pin U)
. (Active = low) When active indicates that the
fan is locked when
Pin U
(+) is connected by open collector to
ground (
Pin W
). Maximum open voltage is 20 volts and maximum
switched current is 3 mA. The switch is an isolated photo-coupler.
A Fan Lock signal is caused by either a fan failure or some object is
interfering with the rotation of the fan.
••
Control/Status Return (Pin W)
. Common return.
Analog Status Circuits
••
RF Output Power (Pin b)
. This pin is not active on the
Multi-Band TWTA.
••
Helix Current (Pin D)
. The TWT's helix current may be determined
by monitoring the voltage in
Pin D
. There is 2 mA of current for
each volt measured.
••
High Voltage Monitor (Pin L)
. The high voltage level may be
determined by monitoring the voltage in
Pin L
. This output is
proportional to the high voltage (1V/1000 VDC).
••
Analog Signal Return (Pin N)
. Common return.
••
TWT Temperature (Pin P)
. The TWT's collector temperature may
be determined by monitoring the voltage on
Pin P
and referring to
Figure 2-12.
•
Reflected Power (Pin c).
The detector output is nominally 2VDC
for a VSWR of 2.5:1.
Output Voltage Circuits
