This example shows how to use a PLC to control a simple divert mechanism to divert a Carton from a ZPA zone and capture its tracking. This example also illustrates how to use the set downstream arrival function with the PLC to keep the discharging module from generating a jam condition when the Carton is moved from the ZPA zone to the divert lane. The PLC will be connected to Module B.
- Set bit 0 in Accumulation Control for Local Upstream Zone register to instruct this zone to accumulate any Carton that arrives.
- Monitor Arrival Count Local Upstream Zone and Departure Count Local Upstream Zone registers. On the leading edge when these two values become not equal, the PLC knows there is a new arrival. Note that as long as a Carton is physically occupying the upstream zone, these two values will not be equal.
- Upon a successful arrival of a Carton in the upstream zone, then tracking data in Current Upstream Zone Tracking Word 1 and Current Upstream Zone Tracking Word 2 will be valid for the newly arrived Carton
- Set bit 8 of Accumulation Control for Local Upstream Zone register. This will keep Module A from releasing a Carton to Module B while the divert operation is in progress.
- PLC will then initiate it’s divert mechanism.
- When carton reaches PE-1, the PLC will then set bit 9 of the Accumulation Control for Local Upstream Zone register. This will tell Module B that the carton “successfully arrived at its downstream position”.
- Once carton has cleared PE-1, then the PLC should clear bit 9 of the Accumulation Control for Local Upstream Zone register.
- PLC then can clear bit 8 of the Accumulation Control for Local Upstream Zone register to instruct Module A that it is OK to allow the next carton to enter Module B’s upstream zone.
The PLC can simply modify Carton’s tracking data if desired and release the Carton as described in Basic Accumulate and Release section