This article explains various types of machine uptime and downtime, and how these different machine states can affect your downtime and production numbers. Together, these factor into your machine’s OEE numbers.
Unplanned Downtime
This is the unplanned downtime of the machine. Reasons for unplanned downtime include technical or mechanical failures, material or operator issues and others. All downtime periods default to the Unplanned Downtime type unless they are assigned a different type, either automatically by PLC code or manually by a Downtime Tracking user.
Planned Downtime
This is the time during Plant Operating Time that the particular machine is scheduled to not be running. Reasons for planned downtime may include: no material to produce because of a line restraint, breaks, meetings, maintenance and others. Any particular period of downtime measured on a machine can be assigned as Planned Downtime by a Downtime Tracking user or automatically by the system if set up to do so. Downtime Tracking codes for this are defined by a system administrator by setting the Downtime Type to Planned in the Manage Codes function of Downtime Tracking.
Scheduled Downtime
This is the time that the plant or machine is scheduled to not be in operation. Reasons for scheduled downtime include shutdowns, holidays, and other times. This type of scheduled downtime is assigned to a machine through the Downtime Tracking application. Any particular period of downtime measured on a machine can be assigned as Scheduled Downtime by a Downtime Tracking user or automatically by the system if set up to do so. Downtime Tracking codes for this are defined by a system administrator by setting the Downtime Type to Scheduled in the Manage Codes function of Downtime Tracking.
Performance
This is the difference between actual quantity of units produced and theoretical maximum quantity of units produced during the Machine Operating Time. It can be represented in units of time, material or speed. Performance Loss may be sectioned by Performance Downtime and Reduced Speed. Any particular period of downtime measured on a machine can be assigned as Performance Downtime by a Downtime Tracking user or automatically by the system if set up to do so. Downtime Tracking codes are defined for this by a system administrator by setting the Downtime Type to Performance in the Manage Codes function of Downtime Tracking. Reduced Speed is the remaining amount of time lost making the actual quantity of units produced because the average speed of the machine was less than its maximum speed.
Reduced Speed = Performance Loss – Performance Downtime
Planned Production Time
This is the portion of time that the particular machine is scheduled and planned to be available for production operation, sometimes referred to as Loading Time. It is Plant Operating Time minus all Planned Downtime.
Planned Production Time = Plant Operating Time – Planned Downtime
Machine Operating Time
This is the time that the particular machine was actually running production, after taking away all scheduled, planned and unplanned downtime. Also referred to as Uptime, it is the Planned Production Time minus all Unplanned Downtime whether assigned with a reason or not.
Machine Operating Time = Planned Production Time – Unplanned Downtime
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