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Analog Input Example Analog inputs can be used for a variety of purposes. In the
following example, a scale is connected to a load cell. A load
cell is a device that generates an electrical output proportional
to the force applied.
Scale
0 to 10 VDC Analog Signal to PLC
Desired Weight = 25 LBS = 5 VDC
Inspection
Station
Finished
Goods
Inventory
Package Route
Controled by PLC
The load cell in this example converts a value of weight from 0
to 50 pounds into a 0 - 10 VDC analog value. The 0 - 10 VDC load
cell signal is connected to an S7-200 PLC’s analog input.
The analog value applied to the PLC can be used in various
ways. For instance, the actual weight can be compared to a
desired weight for a package. Then, as the package is moved
on a conveyor, the S7-200 PLC can control a gate to direct
packages of varying weight.
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