Truck Dumper - part Deux

[Lorenzo M. Oliver]

Almost 10 years ago I used a Stamp BS2sx to automate a truck dumper. It was written up in the 2006 Parallax Catalog. You can read this story here: http://www.parallax.com/tabid/332/Default.aspx

Now, the client has come back to get some additional features added and to put the Stamp controller on another dumper on site.This involved building three complete BS2px systems (two to be immediately installed plus a spare).

 

The system works with the truck scale at the entrance to the mill. When the truck comes over the scale, a load slip is printed which contains a barcode. The barcode includes information on the product, the chip species, the area which produced the chips, the weight, the time/date and whether a sample needs to be taken. The Stamp board reads the barcode and sends information to the mill PLC to dump the truck, move the out-feed conveyor to the correct pile and to take a product sample when required.

 

For administrative purposes, the truck must get from the scale to the dumper within three hours to minimize the possibility that the incoming chips contaminate the pile being used at the moment. This meant using a real-time clock (DS1302) on the Stamp to compare against the time shown on the barcode.

 

The clock code started out with Chris Savage's clock demo code and was modified to allow easy comparison of the two times and to compensate for times over-lapping midnight. As well, extra code was written to deal with the different length of months, leap year and the change-over to/from daylight saving time. Of course, a method of setting and checking the time was needed as well.

 

The barcode scanner and printer are set to use serial communication at 9600. Also, when setting the time, a computer with communications software (Debug, Hyperterminal, etc) is used to see what's going on.  I've attached the schematics and the code used in slot 0 and slot 1 of the BS2px.
http://forums.parallax.com/forums/default.aspx?f=21&m=458014