Has anyone out there found need to use a PLC interface with a Bar code scanner? The application I am trying to put together would be a system to insure the correct product packaging by simply teaching, in this case a MicroLogix 1100 the correct bar code applied and having an alarm and kick off if an incorrect Bar code is read, fairly simple and straight forward just the logic might be a little tricky? Converting the RS-232 serial messaging to something of a usefull nature. Thank you for your attention to the matter and I would appreciate any helpful knowledge.

 

Hi,
Done it, using a simple barcode scanner through an RS232 > RS485 converter (a
programming lead actually!) into an S7-200 in freeport mode, the resulting
number was used to verify the product.
The Barcode was presented as a number and a return. very easy, as for the
logic, I used the container present signal to provide a window, if a valid
number was not seen within that window, then reject.

Marc Sinclair
http://www.germainesysteems.co.uk

 

The RS232 ports for many PLCs aren't really general purpose and the facilities for handling the ascii returned tend to be rather primative. And most of the reasonably priced scanners are set up for PCs. Still, it can be done and often is. I haven't done this with an 1100 but if you can poll the port you should be able to get the string in. There are easier alternatives, like barcode readers that will give you digital outputs for read and pass/fail. I have used a camera for this also because it was cheap and easy for me. Any of the newer lower priced pattern recognition sensors will do this as well.

Regards
cww

 

We use a number of bar code readers, and have found it necessary to send the actual data read to the PLC to compare to a stored copy of what is expected for that product model. We have tried in the past using the internal "compare" function in the reader, but then ended up sending products to the customer with the wrong label.

The problem with a "teach" operation on each product change over is that you are relying on the operating personnel to never make a mistake. If people never made mistakes, most applications probably wouldn't need bar codes. We have also received pre-printed labels with the wrong bar code information on them (the bar code data didn't match the human readable text).

 

Thank you very much for your input! Sounds good.

 

Richard,

Real Time Automation has a gateway to make this very simple for you. It takes ascii data from your barcode scanner and puts it right into a string register or integer register. There is only about 2 rungs of ladder logic.
The unit can send and or receive data.

http://www.rtaautomation.com/ethernetip/435nba/

Rick

 

I have a project with barcode reader and Micrologix PLC.

Micrologix 1100-1200-1500 can read on the RS232 port in ASCII format. But you need to use an industrial scanner like Datalogix or Microscan that scan and convert the barcode into a ASCII string and send it to the PLC by the RS232 port.

After that, the PLC will be able to read the buffer with the appropriate instruction in your ladder.

This type of scanner can vary between $1400 to $1800.

Have fun!

 

Hi there,

I would say that the cheapest and most time-efficient solution is to use a gateway. They are easy to set up. For gateways from Anybus, there are even ready to use configurations. For more information, go to:
http://www.anybus.com/support/support-step.asp?ProdType=Anybus Communicator
and select fieldbus type.
http://www.anybus.com/products/abcverified.asp

or send me an email at:
[email protected]

/Pat

 

Yes, it sounds like you need a Gateway. A very easy to use Gateway can be found at barcodetoplcgateway.com

Setup is easy and the price is right. You can also connect two barcode scanners to one PLC.