MSComm and a Scanner
in [Visual Studio]
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From: J French on 3 Dec 2006 06:23 On Sat, 2 Dec 2006 10:28:07 -0500, "Jim Mack" <jmack(a)mdxi.nospam.com> wrote: >J French wrote: >>=20 >> Maybe the RS232 is really running through a network and there is some >> sort of buffered timeout on the send side. >>=20 >> I've seen similar stuff with printers taking an age to start. >Could be, but I'm skeptical. We'd need to know how the scanner is = >connected and if the behavior occurs when the scanner is directly = >connected to the PC. Agreed >Either way, the OP's understanding of how MSComm operates is not = >complete, since it does not on its own initiate conversations. =20 Also agreed >Whatever this is, it's more likely to be at the scanner end than at the = >PC end. If the PC were blindly reading every 3-4 minutes, you'd expect = >a large variation in response times since the scanning and the reading = >would not be synchronous -- a scan would sometimes occur right before a = >read, and sometimes right after one. I would still like to test it connected directly to the PC with a standard RS232 cable - you remember that RS232 <-> USB problem I had on fast machines, when the lines did not come up fast enough - that experience made me suspicious of 'connections'
From: Henning on 3 Dec 2006 07:34 "Dave" <davegp2(a)msn.com> skrev i meddelandet news:1165121145.782616.127460(a)80g2000cwy.googlegroups.com... > Thank you all for your informative and prompt replies! > > Your information is very valuable in that I'm somewhat of a rookie > here. My code writing abilities are strong enough to keep the big guys > happy, but my knowledge of hardware connections is very limited. > Here are the specs: Out in the shop we have a Symbol brand > "Hotshot" scanner hooked to a PSC PowerWedge, hooked then to an ICPCON > model i-7188E1 Internet Communication Controller (a little blue box the > size of a pack of cigarettes) that is hooked up to the ethernet. Then > it goes to the hub and then my PC. > I can't show you my code right now 'cause I'm at home and my code is at > work. BUT....I still do not think this is a code issue. All I did was > put my code into an MSComm event (like a control button's click event) > and send the Scanned string to an Access database. What I am trying to > figure out is why it takes 3 minutes for the scanned string to get to > the form's textbox. > > Thank you again for your informative input. > > Dave > > If I understand that right, this is the chain. Symbol Barcode Scanner <direct connect> PSC PowerWedge <RS232> ICPCON 7188E <ethernet> HUB <ethernet> YourPC Where is the MSCOMM involved? Isn't WinSock the proper interface here? Have I missed something here? /Henning
From: Dave on 4 Dec 2006 00:07 (original poster responds:) You understand the conection exactly. The MSComm is in my VB program on the PC that is connected to the hub. Should I try the Winsock? Dave PS: Thank you guys again, you are going to make my week go much better. > If I understand that right, this is the chain. > Symbol Barcode Scanner > <direct connect> > PSC PowerWedge > <RS232> > ICPCON 7188E > <ethernet> > HUB > <ethernet> > YourPC > Where is the MSCOMM involved? Isn't WinSock the proper interface here? Have > I missed something here? > > /Henning
From: Henning on 4 Dec 2006 20:12 Hi Dave, Excuse me for starting to feel a little dizzy. Do we really talk about an ETHERNET hub? If so, how on earth can you get any data from the scanner with MSComm???? Are you sure that it is not an USB hub, and an USB to RS232 cable to your computer? Is there another connection? _IF_ wer'e talking ethernet, then the ICPCON should, as I see it, send scanned codes as UDP messages to your computer. For sfest and fastest connection using static IP-addresses. If your network has a DNS-server, reserve some addresses for static use. I don't know the possibilities with ICPCON, you or someone else can tell if UDP is possible. Really, sort me out plz...... /Henning "Dave" <davegp2(a)msn.com> skrev i meddelandet news:1165208852.425102.47240(a)f1g2000cwa.googlegroups.com... > (original poster responds:) > You understand the conection exactly. The MSComm is in my VB program > on the PC that is connected to the hub. Should I try the Winsock? > > Dave > PS: Thank you guys again, you are going to make my week go much better. > > > > If I understand that right, this is the chain. > > Symbol Barcode Scanner > > <direct connect> > > PSC PowerWedge > > <RS232> > > ICPCON 7188E > > <ethernet> > > HUB > > <ethernet> > > YourPC > > Where is the MSCOMM involved? Isn't WinSock the proper interface here? Have > > I missed something here? > > > > /Henning >
From: Dave on 5 Dec 2006 13:44
Henning wrote: > Hi Dave, > > Excuse me for starting to feel a little dizzy. Do we really talk about an > ETHERNET hub? If so, how on earth can you get any data from the scanner with > MSComm???? Are you sure that it is not an USB hub, and an USB to RS232 cable > to your computer? Is there another connection? > Hi Mr. Henning and All, Thank you (all) for staying current on this post. I am sorry for your "dizzy" feeling and I will try to clear it up. I may have I used the term "hub" too loosely. I am a retrained manufacturing (production - inventory control) guy who years ago lost his tractor manufacturing job due to plant closure. Forgive my rookie status when it comes to things LAN based. We have a part-time network administrator (private consultant & very capable) who does the LAN stuff. He said this is not a "USB Hub" hookup. To connect the scanner originally (two years ago) he says it's really going through a switch not a hub over a CAT cable via a MAC address. (HTH). You understand the connection precisely Scanner > PowerWedge > to the LAN. To answer your question about how the MSComm is involved: When we installed the scanner (for light duty) I simply dropped an MSComm control on a form and in the "Private Sub MSComm1_OnComm()" event I placed the following code "Text1.Text = MSComm1.Input." That line reads the scanner. It has worked fine for 2 years; the only other code in that event is a little string manipulation, and I send it to another sub to store it as a record in an Access db table. The app reads the string every 3:05 minutes, (based on the Scan time) plus or minus a second or two. This time delay has not been a problem in the past, but sooner-or-later it will be. I just assumed in the past that the MSComm control sent out some kind of read signal to the COM port on based on an internal timer but I was informed here, that's not how it works. The fact that the delay is based upon the scan time, that alone should have told me this is a scanner based delay, not an MSComm issue. As you suggested, should I be trying the Winsock? I hope this "sorts" you (and all other helpful posters) out as you put it. Thanks again (everyone here) for your responses and questions... hope you may be able to straighten up my "dizziness" here J. Dave |