1-25. NIGHTSIDE TEST BENCH 2A3
Refer to FO-31 for a block diagram of the nightside test bench. The pneumatic
control panel is located in the front of the nightside test bench, but is not dis-
Refer to paragraph 1-22 for description of pneumatic control panel.
b. NIGHTSIDE OPTICAL ASSEMBLY 2A3A1
The nightside optical assembly provides program controlled infra-
red (IR) signals to the TADS nightside assembly and PNVS UUTs. The nightside
optical assembly contains three heat sources, designated A, B, and C, which are
controlled by the control unit assembly 1A1.
Heat sources A and B are in the heat
source target assembly and heat source C (secondary heat source) is inside the
nightside test bench optical assembly, directly behind the shutter assembly. The
nightside optical assembly contains the following assemblies:
Heat source target assembly 2A3A1A1
Shutter assembly 2A3A1A2
Sensor mount assembly 2A3A1A3
Secondary heat source assembly 2A3A1A17
(2) Heat Source Target Assembly 2A3A1A1.
(a) Heat sources A and B are mounted above the aperture wheel and target
The aperture wheel and target wheel are used in conjunction with
the heat sources to provide the stimulus pattern for performing various IR tests.
Five mirrors are used to collimate the energy and route it to the output port where
the UUT is mounted.
(b) The target wheel and aperture wheel are driven to different positions
depending upon the test requirement. The target wheel, mounted below the aperture
wheel, has 10 positions, and the aperture wheel has four.
A single four-phase
stepper motor, which drives both wheels through two magnetic clutches (one for each
wheel), is activated by signals NST EN1, NST EN2, NST 01-NST 04 from the motor con-
trol CCAs in the electronics drawer assembly 2A2A7.
Each clutch rotates a coupling
to a gear train which drives a belt on a sprocket, which in turn moves the target
wheel and aperture wheel.
(3) Shutter Assembly 2A3A1A2.
The shutter assembly provides a protective over-
lapping cover to the nightside optical assembly.
IR SHUTTER OPEN signal from the
motor control CCAs in the electronic drawer assembly 2A2A7 causes a rotary solenoid
to drive an arm to rotate the shutter ring.
Rotation of the ring pulls open the
seven shutter vanes, and a coiled spring provides closure.
Two mechanical stops are
mounted on the bottom of the ring to limit rotation.
Two optical sensors send IR
SHUTTER OPEN and IR SHUTTER CLOSED signals to the multiprogrammer assembly 2A2A6.