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Industrial Automation



Peters and Brownes Balcatta W.A.

This installation features four stacker cranes, servicing the freezer high rise store, and eight shuttles servicing their infeeds and outfeeds.

One of the more interesting features of this installation was that the cabin onboard the crane needed to move up and down the mast by about a metre or so, so that the cabin did not interfere with the top rail while the crane was at the top level and cabin did not interfere with the bottom rail while the crane was at the top.

The crane rail was somewhat rough, causing the crane to be jolted against its mast as it travelled along. Often the crane would complete its hoist travel, prior to completing its long travel, causing the crane to be sitting in the one position on the mast, causing indents there as the long travel continued. This would subsequently cause problems with the hoist positioning. So to compensate for this, the hoist travel was slowed so as to complete as near as possible to the time that the long travel completes, so that the dents would be distributed randomly along the mast, rather than collected at the hoist stop positions. To achieve this, the crane PLC needed to maintain a table of the times it takes for each long travel distance and each hoist travel distance, and, by machine learning, adjust its hoist speed, to time the completion of the hoist travel to coincide with the completion of the long travel.

Communications between the “Movement Controller”and the cranes is via an infra-red serial link.

Communications between the “Movement Controller”and the host computer system is via FTP/TCP-IP/Ethernet.

All PLCs are Allen-Bradley.

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