Barcode scanner interface

I am working with a supplier on a print-and-apply case labeler. Originally, there was going to be one Microscan barcode reader to verify the barcode on the applied label. We figured that we would interface the barcode reader with the serial port on the PLC, Micrologix 1100. We would then use the ethernet port to interface the HMI, Panelview Plus. Now, three additional barcode scanners have been added (total of four) to the labeler. In addition, the system will portable and be available for use on any one of our packaging lines. This requirement makes our normal means of interacing barcode scanners on a packaging line not applicable. We normally inteface a barcode scanner using a Lantronics ethernet to serial converter. Then the operator uses the line SCADA, RSView SE, to download codes to the scanner using a simple VBA script. My first thought was to upgrade the HMI to a PC panel using RSView SE and utilize the same VBA scripting. Are there better alternatives? This seems pretty complicated for a simple labeler.

PLC solution

I guess that another solution is to upgrade the PLC to a CompactLogix or MicroLogix 1500 and add a couple of Prosoft serial interface cards to speak ASCII to the barcode scanners. I have no experience with using ASCII instructions but this seems like a straightfoward solution.

infineum,

We normally inteface a barcode scanner using a Lantronics ethernet to serial converter.

Click to expand...

If the barcode reader has ethernet, why not buy an Ethernet switch & hook all the readers, PLC & HMI together?

My $0.02 BD

Barcode Interface

I would place all of the scanners on an ethernet network and interface to the RSViewSE application via a serial port emulator running on the HMI computer.

Is it possible to send ASCII commands over the ethernet port on a micrologix PLC?

http://www.rtaautomation.com/ethernetip/490nba/

AB doesn't support raw ASCII over TCP (except on the 1756-EWEB) but you can use a module like the one above to accomplish this.

But then the setup gets messy with serial servers talking to add on modules. Way too many failure points in my opinion.

You may want to do some research into barcode scanners that have built in devicenet or Ethernet/IP capability.

Edited to add:

We have a setup where we use a little bit of VB code running in RSView to handle incoming TCP connections from serial servers connected to our barcode scanners. I'm personally not a fan because the VB code craps out occasionaly and takes RSView down with it, but if it was implemented properly it would probably do the job just fine.

The DeviceMaster UP 4-Port model supports 4 serial devices and 4 TCP/IP devices, and makes the conversion between TCP/IP and Ethernet/IP easy. Simply assign a tag in the PLC, and configure the DeviceMaster UP for write-to-tag.

C O M T R O L part number 99447-3
http://www.c o m t r o l.com/products/specs/specs.asp?product=99447-3
(You'll have to remove the spaces in the web address)

I hope this helps!

RSView and VBA

I agree that VB scripting issues could cause problems in RSView. For the most part, we have experienced minor issues with our barcode scanner interface however.
I will probably opt for upgrading to compactlogix with two Prosoft serial interface cards.

Serial Switch

I have used a serial switch before to interface 10 barcode scanners to 1 serial port on a ControlLogix processor. The trick is you have to assign the barcode scanners with unique header characters so you can tell them apart. I used a cheap datalogic D200 and it worked great, saved a lot of money too.

You could also use gateways, instead of prosoft cards.
Set up the Micrologix as a Modbus RTU master.
The anybus Communicator, for example, can act as a Modbus RTU slav on one side and handle communication with the barcode reader on the other side.
see:
http://www.anybus.com/support/support.asp?PID=317&ProductType=Anybus Communicator

Good luck with the project.

Patrick Lansdorf
HMS

abux_77 said:

I have used a serial switch before to interface 10 barcode scanners to 1 serial port on a ControlLogix processor. The trick is you have to assign the barcode scanners with unique header characters so you can tell them apart. I used a cheap datalogic D200 and it worked great, saved a lot of money too.

Click to expand...

Do you recall what serial switch you used. I'm working on a similar project now.

Async Data Sharing Unit

The unit I used is made by Data Comm for Business and is called an ASU - Async Data Sharing Unit

http://www.dcbnet.com/datasheet/asuds.html

It worked really well, and has been in operation for 6 or 7 years now. It has to be set up using hyperterminal and I remember they even added a time delay function to their firmware for us, to give us a small delay between data from different ports so that we wouldn't mistake 2 different scans for one. Worked great and great tech support from those guys, I would use it again.

If you are using scanners that support RS485 then you won't need this as that can handle multiple scanner at once. I also used an HMS AnyBus serial to Controlnet adapter and it didn't handle a lot of traffic very well, going native to RS232 worked better for me.

i´ve ben using dataman bar code reader from cognex with no problem.