This installation features a basket loader and unloader, a small basket
(heavy-unit-load) conveyor system, a can line and a single filer.
The cans of corn from the production line were assembled into layers and
loaded into baskets by the basket loader. The basket was then conveyed to the
cookers. After cooking the baskets were conveyed to the unloader, from there
the cans were unloaded and sent to packaging via the single filer. Meanwhile,
the emptied basket was conveyed back to the loader for refilling.
In this instance, the PLC code for the loaders and unloaders was produced
in the traditional way, so regular SCADA features were added to the
“Movement Controller”to present the status of these machines.
To the right, is shown the mimic of the conveyor system, along with the
SCADA presentation of the loader. The loader is located at conveyor position
“M19A” (where there is a green bar above a conveyor at the base of
the display), while the unloader is located at conveyor “M10A”
(where there is a green bar below a conveyor at the top of the display). In
the loader mimic, the can-line conveyor is stopped (black), while the loader's
conveyor continues to run (green), with its rear photocell clear (the yellow
line) and the next two photocells blocked (shown by the representations of the
tops of the cans). Between the second and third photocells, is the can clamp,
which lowers to hold back further cans from entering the loader once sufficient
cans have been accumulated. Then there is the semicircle representing the
device that collects these cans. Once sufficient cans have been collected, the
device closes, forming a circle, then drags its collection of cans to the left
onto a divider within the basket (shown by a full circle). Below all this, to
the right, is the representation of the divider dispenser (there is a divider
used to support each layer of cans in the basket). Then to the left of that is
the representation of the mechanism that lowers the layers of cans into the
basket, in preparation for the next layer of cans.
The conveyor system incorporates access gates, basket tippers,
pedestrian pressure plates, and simultaneous transfers through the basket
loader and unloader stations.
All PLCs are Allen-Bradley.
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