Automatic

conveyor sorter

PLC Control and Programming

Teacher Pan Shenghu

Team of three

PLC

Siemens S7-1200

Sensors

Pneumatics

SolidWorks

I designed, built and programmed a sorter that separates metal parts from other parts on a moving belt. A Siemens S7-1200 PLC (CPU 1212C) reads a photoelectric sensor and an inductive sensor, and a pneumatic cylinder pushes the selected parts off the belt.

97.5%

material classification

95.0%

photoelectric detection

4.222 s

cycle time

93.6%

availability over 30 minutes

What

I did

Wrote the program in the TIA Portal for the S7-1200.

Set the belt at 250 mm and 30 rpm and measured 0.0777 m/s, which is 1.11% below the target.

Ran the pneumatic pusher, a 20 by 100 mm cylinder, at 0.5 MPa.

Ran 40 objects through the sorter.

Ran a 30-minute availability test, which gave 97.1% sorting accuracy.

+ Honest result

Where it fell short

Sorting accuracy over the 40 objects was 95.0% as I recorded it. Under two stricter definitions it is 90.0% and 85.0%. The 95% confidence interval runs from 83.5% to 98.6%. The classification step reached a precision of 96.6% and a recall of 100%. I put all of this in the report rather than keep the best number.

Pan Shenghu ranked this project first in class. My second project for him, a full SolidWorks, ANSYS and CNC design of the sorter, was also ranked first.