7. Transitions
Transitions refer to movement of an item from a source to destination region.
- Transition indicators: guidelines
- Transition types
Transition Indicators: Guidelines
A region transition indicator reports the movement of an item between two tracking regions.
- Each transition indicator defines unique routes that exist between two regions.
A transition indicator is therefore the:
- Exit transition indicator for the source tracking region and
- Entry transition indicator for the destination tracking region.
- The same transition indicator may specify a valid route between two regions for more than one Item Type.
- When a region entry transition Indicator is received by PRT, PRT updates its tracking data regardless of what tripped the indicator.
PRT cannot distinguish between valid item transition indications it receives and accidental item transition indications it receives (e.g. person walks in front of limit switch, PRT receives the transition indication and updates the system to reflect Item movement).
- Production start must always occur in a tracking region with an entry transition indicator that is not the exit transition indicator for any other tracking region.
Transition types
Limit switch. | |
Type detector. | |
Item identifier. | |
Reference identifier. | |
Associate reference ID to Item. | |
Associate Item Type to item. | |
Positive edge trigger. | |
Negative edge trigger. |