Hi Steve,
Thanks, that's great info and plenty to get us going. I can see it's
going to be a fun learning experience!
Cheers,
Gary
Sustainable Solutions
On 20/09/2018 13:50, Stephen J. Orth wrote:
Guy,
Good Morning...
I'm not sure where you got the concept USB readers are unreliable....in what
way? What brand have you used to cause this impression?
Most all scanners on the market today are interfaced to the PC via USB because more and more PC
vendor's are eliminating the DB9 connector used for RS-232. I would say "unreliable"
describes the RS232 -> USB adapters, as we have never been able to make these work. I've
not used an RS232 -> Ethernet adapter so I cannot comment on this.
We only use Symbol or Zebra hardware for any of our projects. I don't know what
"low resource" environment means but there are good options from these guys for
wireless handheld scanners that use a USB or Blue Tooth base station for communication to
the PC. We are always working in a shop floor environment, so if we cheap out on the
hardware it will simply break and then have to be replaced.
As far as RS-232 settings, this will depend upon how the scanner can be
configured. This is rather straight forward as long as you can determine what
configuration (i.e. baud rate, stop bits, speed, and so on) the scanner is
configured for (or you set). We typically use a COM utility to test with
first, before attempting with 4D. These types of programs make it easier to
change settings and determine if you have successful communication to the
device. Once we know we have communication, then we move to 4D next. We have
just found this process less frustrating...
You will definitely need at least two separate processes running on the
computer, which are completely separate from any interface you may go in/out
of. I say two as this is the only way to ensure you never miss a scan:
1. Listener - This method is specifically designed to only listen for incoming data and
push it to another method for processing. We never try to listen and process the data in
the same method, bad things happen. Basically, this method is creating a "data
stack" to ensure requests are received and processed in order.
2. Processor - This method is utilized as the primary vehicle for processing
all incoming scans.
One piece of advice, if you have control over the bar codes being scanned, make
sure they have embedded codes to identify them as valid transactions. Users
wills can almost anything so you need to be able to separate valid/invalid
scans.
Best,
Steve
*********************************************
Stephen J. Orth
The Aquila Group, Inc. Office: (608) 834-9213
P.O. Box 690 Mobile: (608) 347-6447
Sun Prairie, WI 53590
E-Mail: s.o...@the-aquila-group.com
*********************************************
-----Original Message-----
From: Gary Willetts [mailto:g...@sussol.net]
Sent: Thursday, September 20, 2018 2:53 AM
To: s.o...@the-aquila-group.com; '4D iNug Technical' <4d_tech@lists.4d.com>
Subject: Re: How to tie 4D to barcode readers?
Hi Steve,
Sorry to be unclear - what I meant is that we're not wanting to read
data from barcode scanners into a specific field in the GUI, we just
want to be able to read it and process it as it's scanned.
How we do it will probably be dependant on the type of scanner we use:
we understand USB is relatively unreliable (correct me if I'm wrong) and
IP readers are pricey. We're working in a low resource setting so we
need to look at lower priced readers. That seems to leave us with
RS232/serial readers. But something I discovered yesterday is that you
can get RS232 to Ethernet adapters which might help - or not! Any wisdom
you have here would be appreciated.
Either way, I'm guessing we'll need a separate process that listens to
the reader, whether it be on a serial port or over TCP/IP. I'd be
interested in any advice you can give in identifying the port or other
things we should be aware of, given we're in a Windows environment.
Cheers,
Gary
Sustainable Solutions
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