Symbol FZ barcode scanner not reading properly in LV7.1

[Underflow]

Hey all,

We're upgrading a computer to a much faster version, and having an issue with a new barcode scanner (a Symbol FZ). The scanner is in line with the USB keyboard, and emulates keyboard input, appending a linefeed after scanning the barcode. The keyboard attached to the scanner works fine, no matter how fast you mash the keys.

Under Word, Wordpad, Notepad, or anything else I've tried, the scanner works flawlessly. Under LabVIEW, the scanner (apparently randomly) drops or adds characters. So far, it's dropped the terminal linefeed, added a terminal "J", and prepended an initial "/". The failure initially occurred in an executable, but also occurs in a single string control on an empty, non-running VI. The failure occurs consitently after reboot, that is, if it decides to drop the terminal linefeed, it continues to drop the terminal linefeed until the machine is rebooted. The error occurs under any state that I have been able to put the string control in: update while typing, display symbols, etc.

I'm grinding through the (432 page!) Symbol FZ manual in hopes of finding a clue, but any help would be appreciated.

Thanks,

Joe Zoller
Test Engineer
Picolight, Inc
Boulder, CO

[LoganS]

What exactly do you mean "under LabVIEW" as compared to to "under Word..."? Is there some ready made software or a driver that generates a file that you can view in a text editor or LabVIEW? Is this just a file parsing issue? If so, is it possible to post an example file that can be opened in an editor, and a simplified version of your LabVIEW program that you're using to parse the file? Please advise if the problem isn't a file I/O issue, and we'll go from there.

Logan S.

[Underflow]

There is no driver for the scanner (well, it's internal to the scanner anyway), it just duplicates the keyboard signal to the computer. More info on the scanner can be found at:
http://www.symbol.com/products/barcode_scanners/ls3400fz.html

The process I'm using to test the issue:

-The barcode scanner is inline with the keyboard.
-A program is opened (LabVIEW, Wordpad, etc) and focus is set in a text field.
-A known barcode is scanned using the scanner, duplicating keyboard input.
-The text field is checked for accuracy vs. the known value of the barcode.

LabVIEW doesn't get the correct value, other programs do.

We're pursuing several hardware issues (swapping cables, scanners, reconfiguring the scanner, etc), but it will be a little while before that's finished.

Any ideas?

[Dennis_Knutson]

Hi neighbor,

Unfortunately, I don't have any ideas right now. But, we have on order a couple of new USB keyboards and scanners for some new projects we're working on. I believe the brand of scanner we ordered was PSC. I don't know the keyboard. We've never had any problems with our traditional keyboards and scanners. I'll post back when we get the new stuff and I get a chance to try them out.

[Underflow]

Hey Dennis, thanks for the reply (and thanks to LoganS above as well).

We're checking the USB connection on this now, though it will probably be a few days before the cables arrive. I'm beginning to think it's really just a scanner issue, but that LabVIEW is particularly susceptible to it due to some subtle change in the way LV handles input compared to MS based programs. Perhaps LV is a touch slower or faster at recognizing keyboard input.

Careful outside now neighbor, it only *looks* warm! 🙂

Joe Z.

[LoganS]

I heard through the grape-vine that this is still an issue for you. A couple other application engineers put together the attached VI. It's set to respond to events, such as key presses (what your scanner should create), with no delays, so we can rule out timing as the issue. If you wouldn't mind trying this out and letting us know what kind of results you are getting, we'd appreciate it.

Also, Dennis - did you ever get the scanners you mentioned? Did you encounter any similar problems?

-Logan S.

[Dennis_Knutson]

As a matter of fact, we just got one in. I had one plugged into my pc with no problems, a pc in the lab with no problems, and then moved it to one of of the production testers where it has been running fine for the last two days. On my pc, I used both LabVIEW 7.0 and 7.1. On the production tester, it's running only 7.0. None of the pc's are very fast though. I think the fastest pc is around 1Mhz. I've been trying to get IS to let me borrow something newer. The brand of scanner we got is ID Automation SC5USB. All pc's are running win2k.

Joe,
When we get some more in, would you want to borrow it for a day or so?

[Underflow]

LoganS,

Nice little program, wish I'd thought of it! Please thank those responsible for it. It pinpoints the problem well, though the solution may be beyond LabVIEW's scope.

On to the data,

Development environment, hand typed (with right shiftlock):
Input string: 12345ABCDE
Scancode list: 2 3 4 5 6 30 48 46 32 18 54
Output string: 12345ABCDE

Development environment, from the scanner:
Input barcode: 12345ABCDE
Scancode list: 2 3 4 5 6 42 30 42 48 42 46 42 32 42 18 29 36 28
Output string: 12345ABCDE

Executable, from the scanner:
Input barcode: 12345ABCDE
Scancode list: 2 3 4 5 6 42 30 42 48 42 46 42 32 42 18 29 36 28
Output string: 12345ABCDEj\n

Executable, from a different, older scanner:
Input barcode: 12345ABCDE
Scancode list: 2 3 4 5 6 30 48 46 32 18 42 28
Output string: 12345ABCDE\n

Obviously, something is amiss.

28 = \n
29 = Ctrl
42 = Left Shift
36 = J or j
54 = Right Shift

The scanner is throwing a ctrl-j in at the end of the scan. The development system, and Windows-based programs, discard the ctrl-j. Why is it there? I haven't a clue. Why have I seen prepended slashes and other behavior? Again, no idea. After calling Symbol, they don't know either.

I've reconfigured the scanner from scratch, and the input stream is... different. If I can figure out exactly what's going on, I'll post back here. I have a strong suspicion I'll never know.

Thank you for all your help folks! Much credit to NI for not leaving me hanging out in the wind on this one, which they certainly could have done. More credit to the LV engineers for making a product that did exactly what it was supposed to do with the input handed to it.

Dennis,

Thank you for the kind offer, I think we will manage without. If necessary, we have other scanners that we can adapt to suit, and we'll try to get Symbol to refund us on this one. And you answered my next question in advance, with the model type!

Joe Zoller

[ben7670]

Hi Dennis,
How do you connect your scanner to PC, does it connect via USB port or RS232 port and what labview VI do you use for decoding from scanner. please help i am new for this stuff.
Thanks
Ben

[Dennis_Knutson]

My USB scanner, I connect to a USB port. My other scanners are a keyboard wedge type and I connect them between the keyboard cable. The USB type is detected by the system as another keyboard. The wedge type is transparent - the system doesn't see a new device - it's just part of the keyboard. In both cases, because they're just a keyboard, no VI is required to read them. A string control will detect whatever is scanned just as if you typed it in from the keyboard. Most scanners will automatically append a CR at the end so you'll have to handle this. One way is to go to Tools>Options>Front Panel and select "End text entry with enter key".