Cable End Electrical Assemblies and Precision Measurement Processor Miscellaneous interlocks, switches and accessories
p/n 6510020208
10/18/07
6-35
Additionally, the detector voltage comparison output is logically ANDed
with the X-ray shutter command signal. The logic tests for two source
failure modes:
•
The conditions of the first source failure mode are a shutter-closed
command and an above-threshold value for the signal. This
condition indicates that the shutter is stuck open.
•
The conditions of the second failure mode are a shutter-open
command and a below-threshold level for the signal. This condition
indicates that either the shutter is stuck closed or that there is a
failed source or receiver, or a source/receiver (head) separation.
This mode can also be triggered by a very thick/heavy product in
the air gap.
Two contact outputs are associated with this failure detection logic:
•
The first provides a power interlock when conditions are normal.
This interlock goes to the Ash Power Relay on the Termination
Board. When the power interlock is removed, 24V power to the Ash
source is removed.
•
The second provides an alarm contact if a failure is detected.
6.6.4.3.
Preventing false triggering
To prevent false triggering during shutter state changes, the Radiation
Fault/Protect board has a selectable delay that is set with the W1 shunts.
This delay starts when the shutter is either opened or closed. During the
delay, a fault condition will not disable power interlock. See Table 6-13 for
the delay times. Do not select a delay that is longer than necessary.
Table 6-13 False Trigger Delay
W1 Shunts
Delay Set
All W1 shunts removed
5 sec ± 0.5 sec
Shunts for pins 2-7, 3-6, and 4-5 removed
4 sec ± 0.5 sec
Shunts for pins 3-6 and 4-5 removed
3 sec ± 0.5 sec
Shunt for pins 4-5 removed
2 sec ± 0.5 sec
No W1 shunts removed
1 sec ± 0.5 sec
Summary of Contents for 4022
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