Barcodes

[Guest Slick504]

Can anyone tell me any web sites or manuals that will give me an idiots guide to barcodes and scanners. Such as what is a prefix and suffix, why are they used. Got to install a scanner via a basic module in a 5/04, so the barcode can be displayed on a panelview. Any help appreciated Cheers Graeme

[Chris Elston 78]

I got in my hands a small book made by A-B that I think is pretty good. Called: Bar Code Basics Publication: 2755-921 I don't know if you can find that any where free on the web or not. I also assume they have a newer version of this book somewhere, as this one is rather old. The reason I use prefixes is so you can tell which barcode reader it came from and suffix so you know when the string has ended. Example: If I have four bar code readers that are wired RS-485 into a MUX (mulitplexor), then I connect my MUX via RS-232 direct to my serial port on my front port of my 5/03, I need to know what strings are coming from what bar code. So I setup a prefix different from each of the four bar code readers. string #1 = /1/ ABCD123 /n/ came from bar code #1 string #2 = /2/ ABCD123 /n/ came from bar code #2 string #3 = /3/ ABCD123 /n/ came from bar code #3 string #4 = /4/ ABCD123 /n/ came from bar code #4 If you are monitoring your buffer on your 5/03 you might get this for a string in one scan: /2/ ABCD123 /n/ /4/ ABCD123 /n/ /1/ ABCD123 /n/ So you have to decode that into useful information, by looking for a prefix, and then your "DATA" and know when your data ends by looking for a suffix. The readers I like to use are DataLogic RASTER scanner 500 lines per second, and DataLogic's MUX32 module, and just a plain old serial port on the front of the SLC 5/03. I don't like to fight the basic module, and I can write all my code in ladder logic for my bar code readers. Fight the basic module, meaning I need more practice on using it before I say I like it. In the Datalogic setup software, you can define anything you want for a prefix and suffix strings. I am pretty sure you can do that in any reader also. Hope that helps.