Housekeeping moves containers to more optimal stacks well in advance of the exit move from the ASC block, that is, before the exit move has a move time. The goal of housekeeping moves is to move containers to stacks that will have a significantly better Expert Decking score. The threshold of what the scoring difference must be for the move to be considered is configured by PHTSITparameter. Since these moves are considered low-priority/not urgent, they are executed when there are no other high-priority productive moves (loads/discharges).
Also see: Explain ASC housekeeping moves, Preposition moves (on page 1), Tune yard move service times (on page 1)
Location of container |
In the ASC block |
---|---|
Move kind |
YARD |
WA Move Purpose |
HOUSEKEEPING |
Decking Invoked |
Expert Decking on XPS client |
When housekeeping is considered |
|
When housekeeping is not considered |
|
Configuration that impacts housekeeping |
PHTSIT, PHTTAC, PHTTTO, PHTMHT, PHTTPA, OPTHID OPTHID determines the time the ASC must be idle before housekeeping is considered. The PHTLIT threshold does not apply for housekeeping moves. The PHTTER EC parameter determines how long the housekeeping cycle runs (set by PHTTAC) before errors are logged. How housekeeping timing parameters work together
HSKUPD must remain turned off for semi-automated sites. |
How to select the range for housekeeping? |
Considers the entire block. |
How is the move reflected in the system? |
Once dispatched, N4 Automation places all housekeeping moves in the BACKGROUND work queue.Make sure the BACKGROUND work queue is active. XPS setting BGWQNM provides the name of the work queue. |
What happens when a housekeeping fails to deck? |
The move isn't done. |
Notes
To keep storage containers in place (to prevent them from getting moved to an inappropriate transfer zone), XPS does not apply the TIMDBE penalty to storage containers.
Manual housekeeping tends to put containers outside of their allocation ranges. The ASC Optimizer does not refine definite moves made in ASC stacks.
Semi-automated terminals can stop XPS from sending ASC blocks' housekeeping calculation updates to N4 by setting HSKUPD to N. When set to N, XPS does not send ASC blocks' housekeeping calculation updates to N4 because the housekeeping activity for semi-automated terminals does not involve the N4 application and hence need not be persisted to the cache/N4. This reduces the overhead on the Bridge.
The housekeeping logic constantly works on improving a container's position for higher crane productivity. Hence when you plan or dispatch a housekeeping move, XPS clears the values of the following attributes and updates them again when Expert Decking finds a better slot for the container.
Housekeeping Current Slot (HKCS)
Housekeeping Future Slot (HKFS)
Housekeeping Current Score (HKCR)
Housekeeping Future Score (HKFR)