F.1.6 General Purpose Scheduled Procedure Step Management States

Figure F.1-3 specifies how changes in the status of a General Purpose Scheduled Procedure Step shall be managed.

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Figure F.1-3: Management of General Purpose Scheduled Procedure Step Status

The SCP will create the General Purpose Scheduled Procedure Step (GP-SPS) with an initial status of SCHEDULED. The availability of the input information is denoted by the Attribute “Input Availability Flag” (0040,4020) . The SCU may start working on a GP-SPS which has the status SCHEDULED, regardless of the availability of the input information. As soon as an SCU starts working on the performance of a GP-SPS, a status modification to IN PROGRESS shall be requested by the SCU. If the status modification to IN PROGRESS is acknowledged, the SCU at the same time has an implicit exclusive lock on the GP-SPS, as long as the status is IN PROGRESS. When the status has a value other than IN PROGRESS, there is no implicit exclusive lock on the GP-SPS.

Once a GP-SPS is started and the status is IN PROGRESS (that is, with an implicit exclusive lock) all subsequent attempts by another SCU to set the status will fail. This failure to set the status will indicate that someone else has already set the status of the GP-SPS to IN PROGRESS and will perform tasks related to it. The SCU that has set the status of the GP-SPS to IN PROGRESS and wants to relinquish control of it before its completion may request a status modification to SUSPENDED or SCHEDULED.

There is no limit on the number of transactions in either direction between IN PROGRESS and SCHEDULED or IN PROGRESS and SUSPENDED.

Once an IN PROGRESS GP-SPS is completed, the SCU shall request a modification of its status to COMPLETED.

The SCU may discontinue an IN PROGRESS GP-SPS at any time, provided the GP-SPS is not completed. To do so, the SCU requests a modification of the GP-SPS status to DISCONTINUED.

The SCP is responsible for defining how long a GP-SPS persists (is visible in worklist) once its status is COMPLETED or DISCONTINUED.

The state information related to the General Purpose Scheduled Procedure Step is specified by the General Purpose Scheduled Procedure Step IOD in the Attribute “General Purpose Scheduled Procedure Step Status” (0040,4001).

Table F.1-5 describes the valid General Purpose Scheduled Procedure Step states, and Table F.1-6 the valid state transitions.

Table F.1-5

GENERAL PURPOSE SCHEDULED PROCEDURE STEP STATES

State Description
Scheduled General Purpose Scheduled Procedure Step created and scheduled to be performed
In Progress General Purpose Scheduled Procedure Step created and execution in progress. This is the only state that implies an exclusive lock.
Suspended Execution of the General Purpose Scheduled Procedure Step temporarily suspended.
Discontinued Execution of General Purpose Scheduled Procedure Step canceled by SCU
Completed General Purpose Scheduled Procedure Step completed by SCU

Table F.1-6

GENERAL PURPOSE SCHEDULED PROCEDURE STEP S TATE TRANSITION DIAGRAM

States
Events Scheduled In Progress Suspended Completed Discontinued
General Purpose Scheduled Procedure Step Started In Progress (SCU)
General Purpose Scheduled Procedure Step Completed Completed (SCU)
General Purpose Scheduled Procedure Step Suspended Suspended (SCU)
General Purpose Scheduled Procedure Step Resumed In Progress (SCU)
General Purpose Scheduled Procedure Step Discontinued Discontinued (SCU)
General Purpose Scheduled Procedure Step Completed Completed (SCP)
General Purpose Scheduled Procedure Step Re-Scheduled Scheduled (SCU) Scheduled (SCP)