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Jack H.Integration and automation of manufacturing systems.2001.pdf
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page 209

vision

left

right

reject

part movement along conveyor

conveyor location sensor

7.22 IMPLEMENTATION

7.23 PLC WIRING

• Many configurations and packages are available. But essential components are:

power supply - Provides voltage/current to drive the electronics (often 5V, +/ - 12V, +/- 24V)

CPU - Where ladder logic is stored and processed; the main control is executed here.

I/O (Input/Output) - A number of input/output terminals to connect to the actual system

Indicator lights - Indicate mode/power and status. These are essential when diagnosing problems.

• Common Configurations:

Rack/Chassis - A rack or number of racks are used to put PLC cards into. These are easy to change, and expand.

Shoebox - A compact, all-in-one unit (about the size of a shoebox) that has limited expansion capabilities. Lower cost and compactness make these ideal for small applications.

• Criteria for evaluation: