Phase failures occur for a multitude of reasons. Simple phase failure occurs when an operator attempts to connect to a procedure that is not idle, or when an operator attempts to run a phase that is owned externally.
Failure to load phase errors generally are the result of (but not limited to) the following:
When a phase failure occurs, an alarm is displayed in the Alarm Summary screen (refer to the Phase Alarms in Unit Modules topic for more information on configuring alarms). These phase failures are defined in the failure register of the process controller and are sent when a phase fails to function properly. For example, when a phase programmed to open a valve fails and the valve remains closed, the phase failure is sent.
A unit phase can fail to be instantiated if the controller does not have enough memory when the phase is run either by the operation or manually by the operator. This will cause a phase failure and, depending on the hold propagation defined in the Batch Executive properties, can cause the higher recipe levels to hold.