Rockwell Automation 5370-CBPK Color CVIM BLISTER-PAK Option - Manual (Page 69)

Chapter 8
Results and Outputs
8–8
Timing requirements for the machine stop output signal are the same as for
any other “results” output.
The results trigger is a handshaking signal that allows a controller or other
device to verify, on an ongoing basis, that the Color CVIM BLISTER-PAK
system is working as it should.
It creates a positive communication link in which a change of state in the
Color CVIM module must occur before a subsequent inspection can take
place. This protocol (illustrated in Figure 8.4) avoids the possibility that a
“stuck” output could misrepresent inspection results when the inspection
window is set for
Active: Pass . Without the results trigger, if an output
remains high due to equipment failure while the window is operating in
Active: Pass , it would appear to external devices that all blisters being
inspected have passed inspection, which may not be the case.
Figure 8.4
Discrete I/O Timing Diagram with Results Trigger Enabled
Analysis
Complete
Inspection Trigger
(To CCVIM Module)
Results
(From CCVIM Module)
Data Valid
(From CCVIM Module)
Results Trigger
(From Controller)
ЙЙЙЙЙ
ЙЙЙЙЙ
ЙЙЙЙЙ
ЙЙЙЙЙ
Analysis
Complete
Likewise, the results trigger avoids the possibility that a power disruption
could lead to an assumption that the system is reporting a continuously
acceptable series of inspections when the active fail function is enabled.
Either of the above scenarios would result in the possibility that failed
inspections could be interpreted by an external device as having passed. By
requiring a change of state in the Color CVIM Module’s output before
allowing the next inspection, the results trigger provides a way to verify that
the output is functioning properly, and eliminates one possible cause of error.
NOTE: The Allen–Bradley remote I/O function incorporates its own
mechanism of ensuring reliable operation through the rack fault bit.
Therefore, the results trigger is used only with local I/O, when
communicating with a non–Allen–Bradley controller. The results trigger
signal is applied to the second input module on the 2801–JMB board.
Results Trigger