Defining loss – Rockwell Automation Arena Packaging Users Guide User Manual
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Q:
What statistics are available for failures?
A:
For each equipment module, Arena Packaging automatically tracks statistics on the
number of failures that occur, the average downtime per failure, and the total time the
equipment is failed.
Q:
Is the Time Span field for the Reliability Over A Time Span option specified in
calendar time?
A:
No. It should be specified as time that the equipment is operational (i.e., time that the
machine or palletizer is actually processing units or time that the conveyor is actually
running).
Q:
What information should I enter in the Expected Uptime field?
A:
Enter the percentage of available operational time (not calendar time) that you expect
the equipment to be up. Available operational time excludes planned downtimes and
times that a machine or palletizer is blocked or starved. Thus, the percentage should
be entered as Operational Time/(Operational Time + Failed Time).
Q:
Suppose that during runtime a failure is scheduled to occur at a module but the equip-
ment is already stopped due to another failure, scheduled stop, changeover, etc. What
happens?
A:
Failures can only occur when a piece of equipment is running (i.e., the speed factor
and run speed of the module are greater than zero). If Arena Packaging generates a
failure for a piece of equipment and that equipment is currently stopped, the failure
waits until the equipment begins running before setting the state variable to Failed and
beginning its downtime.
The exception to this rule involves scenarios where the equipment is already stopped
due to another failure. In those circumstances, the second failure is ignored.
Q:
Can you model the loss of product that is associated with failures?
A:
Yes. This is discussed in the next section.
Defining loss
Another aspect of equipment behavior is the loss that occurs as units are processed or
transferred. This wastage can be expensive and dramatically impact system throughput
and performance.
To define loss for a machine, conveyor, or palletizer, simply check Loss in the Other
Options section of the module’s main dialog box. Then click on the Loss dialog box.