Tracing device.


Thread Starter

Martin Cutajar

Hello ppl.
I need to come up with a device which is capable of tracing shapes from drawings (two dimesions only)into a PLC. This will act as data for a material dressing machine. The accuracy reuired is not high (say 0.5 mm).
I believe I can control the machine well if I can resolve the shapes into a set of orthogonal coordinates pairs. However the only solution I can think of yet, to trace the shapes, is to use a tracing head made up of four photoelectric sensors (the shapes can be drawn in thick lines say 3 mm). The head would follow the shape outline driven by two motors with encoders.
My client is not keen on using a PC and scanner which would be much more reliable and perhaps even cheaper.
Could anyone suggest other economical solutions?

Martin Cutajar

David Graham

Do you have any way to read the encoder outputs directly? If so, you could manually move your XY head while accumulating the encoder pulses. Then just record the totals periodically.
David Graham
Graham Automation, Inc.

Johan Bengtsson

Could you not just “hide” away a PC someware under a scanner or something.
I think you are right about that it would be a easier and cheaper way to solve it but you coulkd make it “hidden” in such a way that the PC have no keyborard, mouse or screen, just a set of cables to the PLC and to the scanner.
Then it is just a matter of placing the drawing in the scanner instead of whereever they would have placed it otherways and press a button someware.
But of course your suggested method would work quite well too but perhaps not very fast.

Johan Bengtsson
P&L, the Academy of Automation
Box 252, S-281 23 H{ssleholm SWEDEN