MIL-PRF-22885H
4.7.32 Logic level circuit (when specified, see 3.1) (see 3.37). Switches shall be tested in accordance with EIA-
448-1, method 17 as follows:
Contact load: Each switch contact shall make, carry, and break a resistive load of 10 mA ±1 mA at an open
a.
circuit voltage of 5.0 V dc ±0.5 V dc. Both normally open and normally closed contacts shall be loaded.
Contacts shall be connected to individual loads.
Cycles of operation: Unless otherwise specified (see 3.1), the number of operations shall be 50,000 cycles.
b.
The actuation rate shall be 120 cycles per minute maximum. Unless otherwise specified (see 3.1), each
stroke of the actuating means shall include the full range of travel from free position to full overtravel position
and return to the fully released position. The actuation force applied to the switch actuator shall not exceed
the force required to reach the extreme position of travel unless so authorized by the manufacturer.
c.
Monitoring: During each closure of the contact, the voltage drop across the switch terminals shall be
monitored for a duration of no less than 50 percent of each contact static closure. The switch contacts need
not be monitored until 10 ms after the initial contact closure to exclude any contact bounce. During each
opening of the contacts, the voltage drop across the switch terminals shall be monitored for a duration of no
less than 50 percent of each contact opening. The monitoring device shall either record the number of
contact closures at which sticks or misses occur, or discontinue the test when sticks or misses occur.
4.7.33 EMI/RFI shielding (when applicable) (see 3.38). Switches which are equipped with EMI/RFI shielding shall
be tested as specified in 4.7.33.1, or when specified (see 3.1), switches shall be tested as specified in 4.7.33.2.
4.7.33.1 Positive grounding. Resistance between the mounting bushing or bezel and the EMI/RFI shield shall be
measured in accordance with method 307 of MIL-STD-202. The following details and exceptions shall apply:
a.
Method of connection: Between a suitable exterior point on the mounting surface and the screen (lens may
be drilled for access to screen).
Test current: 100 milliampers ±10 milliamperes.
b.
Open circuit test voltage: 6 V dc ±1 V dc.
c.
d.
Number of measurements per activation: One in free position and one in full plunger overtravel position.
There shall be no exterior force applied to plunger during measurement of resistance in free position.
4.7.33.2 Shielding efficiency (when specified, see 3.1 and 6.2). Switches shall be tested utilizing a test setup (or
equivalent) as shown on figure 8. Measurements shall be made as follows:
a.
With the door open and the antennas in the "initial setup" position, establish a test level over the 200 MHz to
1 GHz range such that the received signal level is at least as many dB above the RF ambient level as that of
the shielded enclosure attenuation.
b.
Record the received signal level and the signal generator output level. Repeat measurements at 100 MHz,
200 MHz, 400 MHz, 600 MHz, 800 MHz and 1,000 MHz.
c.
Move the antennas to the final test positions, close the door and with an RF-tight blank panel between the
antennas, measure the integrity of the enclosure by setting the signal generator to the same output and
record the received signal level for each frequency used in 4.7.33.2b. The shielded enclosure attenuation is
then calculated using the following equation:
Attenuation (dB) = 20 log E1
E2
d.
Mount the test switch in the blank panel with the rear of the switch outside of the shielded enclosure (toward
the signal generator antenna). The switch shall be mounted as it would be for normal installation using the
mounting hardware supplied or recommended. Repeat the measurements of 4.7.33.2c above and calculate
the shielding attenuation of the switch using the new receiver readings.
34
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business