Rockwell Automation 1752-L24BBBE SmartGuard 600 Controllers User Manual - Manual (Page 245)

Rockwell Automation Publication 1752-UM001E-EN-P - June 2014 245
Function Blocks Command Reference Appendix D
Muting Sequence
The muting sequence for this example is described below.
1. The light is not interrupted between sensors 11, 12, 21, and 22 and the
light curtain, so the Output Enable signal is on.
2. As the workpiece moves to the right and sensors 11 and 12 go on in order,
muting is enabled and the muting signal turns on.
3. As the workpiece continues to advance, the Output Enable signal is kept
on even if the light curtain is obstructed.
4. As the workpiece continues to advance, the light from sensor 21 is no
longer interrupted by the workpiece, the muting status is cleared, and the
muting signal turns off.
Distance Settings
When setting up this type of muting application, the distance settings must
prevent a passing person from enabling the muting function, and the light curtain
and muting sensors must be set up so that a workpiece passes by all of the muting
sensors before the next workpiece arrives at the muting sensors.
To calculate the appropriate setup distances for this example, use these formulas,
where:
D2 and D3 = minimum distance required for muting sensor performance
d2 = maximum distance required for muting sensor performance
L = length of the workpiece
V = transit speed of the workpiece
T1min = controller cycle time
T1max= synchronization time setting (the default setting is 3 seconds)
Formula 3: D2 < L
Formula 4: D3 < L
Formula 5: V x T1min < d2 < V x T1max
For the muting function to operate effectively, formulas 3, 4, and 5 must be
satisfied.