PSC 2000781J MkII MLB Operating Procedure page 31

Step
Prepare to Set-for-Flight the Lightband. See Figure 9-3 and Table 9-1 for the
anticipated current draw and power duration.
Verify the oscilloscope trigger is active and ready to acquire data.
When ready activate the timer relay to Set-for-Flight the Lightband. The motors
will free run for ~1.1 s and then the Sliding Tube will move off the Stow limit
switches. This will be apparent when the current spikes, the Sliding Tube
9.1.11 begins to cycle on and off rapidly, and/or chatter is heard from the Motor
Bracket Assembly. The chatter is the electro-mechanical natural frequency of
the Motor Bracket Assembly.
Manually cut power if the current limit is reached or the timer relay runs longer
than the specified time and contact PSC immediately. A visual inspection of
the Lightband may be performed, but do not change configuration.
Caution: See note 1 below.
De-activate the power supply output.
9.1.12
Save the voltage and current profiles for both motors and verify the data is
9.1.13
readable.
Figure 9-3 shows example Set-for-Flight voltage and current profiles. Complete
Table 9-1 to verify all parameters are within tolerance. Single data point
exceedances are acceptable. Also, a slow sample rate may alias data. Do not
filter data. Contact PSC if a discrepancy is found.
9.1.14
Remember to account for non-zero offsets in the voltage or current
measurements.
Figure 14-1 shows the post Set-for-Flight state of the Motor Bracket Assembly
switches. Measure resistance directly at the Lightband's DB-9 socket
9.1.15
connector by completing Table 14-1. See Figure 16-2.
Contact PSC if a discrepancy is found.
Notes
1) If the oscilloscope used in Figure 9-2 has common ground the negative voltage probes are connected. This
means pins 4 and 8 are connected and the current flow can bypass one of the stow limit switches. Therefore,
both stow limit switches must open before power is cut. This will manifest itself in the current profile as both
motors being perfectly synced, when in reality there may be switch activation differences of a few
milliseconds. See Section 17 for details.
PSC Proprietary
Procedure
2000781J MkII MLB Operating Procedure
Date & Initials
Tech. QA
Page 31 of 50