PCM-22 Rotary Knife Controller
38
© EMERSON Motion Control
LAST REAL SENSOR POSITION
DIRECTION OF TRAVEL
MASTER
SENSOR
INPUT
DEACTIVATED
POST-SENSOR
VALID ZONE
PRE-SENSOR
VALID ZONE
INPUT
DEACTIVATED
POST-SENSOR
VALID ZONE
PRE-SENSOR
VALID ZONE
NEXT EXPECTED SENSOR
LOCATION ONE AVERAGE
LENGTH AWAY
MASTER LENGTH
UPPER LIMIT USED
IN THIS REGION
MASTER LENGTH UPPER LIMIT
MASTER LENGTH
LOWER LIMIT USED
IN THIS REGION
MASTER LENGTH
LOWER LIMIT
Figure 20
Master Length Upper Limit, Master Length Lower Limit and Master
Sensor Valid Zone Operation
Master Length Upper Limit
The
Master Length Upper Limit
performs several functions:
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The
Master Length Upper Limit
must be within the
Master
Sensor Valid Zone
for proper operation.
Missing Master Sensors
When the Master Cycle is Defined by Sensor and the distance from the
last
Zero Master Cycle
sensor input is greater than the 150 percent of
Average Master Length
, the PCM-22 will assume that the Master axis
target was missed. If so, the sync position from the last sensor plus the
Average Master Length
will be used. The
Master Sensor Missing
(output
function 25) and
Cycle Error
(output function 66) will be activated while
the condition is occurring. See the
Master Sensor Missing
output
function, Figure 21 and the
CQ
serial command.
WARNING!
Master Sensor Missing
operation is independent of the
Master Sensor
Valid Zone
. When this condition occurs, it is possible to get into a
situation that sensor targets occur continuously outside the
Master
Sensor Valid Zone
and the system will not return to the correct phase.