Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
?
Solved

COM Port Error Using Excel VBA - Can the Same COM Port Be Used for Output & Input

Posted on 2007-03-19
9
Medium Priority
?
646 Views
Last Modified: 2010-04-30
I'm having a problem with importing data from an analytical balance into an Excel spreadsheet connected via a RS232 serial cable.  I first send a command to the balance to read the weight and then try to capture the input from the com port into Excel.  When I do this i get "Run-Time Error 52".  Here's the code I am using:
========================================================
Open "COM1:12,,0o,7,1" for Output as #1   ' open COM1 port for output
Write #1, Chr(33) + Chr(80) + vbCrLf   ' send command to balance to read weight
Close #1   ' close COM1

Open "COM1:1200,o,7,1" for Input as #1   ' open COM1 port for input
Input #1, strString   ' get input from balance (weight) and assign it to a string variable
ActiveCell = Mid(strStirng,5,6)  ' parse input
ActiveCell.Select
Close #1   ' close COM1
=========================================================
The run-time error comes up on the Input #1 line of code.  Any ideas what might be going on?  Thanks.

Bruce
0
Comment
Question by:bwagner-stl
  • 5
  • 2
7 Comments
 
LVL 45

Expert Comment

by:patrickab
ID: 18747953
Bruce,

Are you sure the balance is sending you a string as opposed to a numerical value?

Patrick
0
 
LVL 45

Expert Comment

by:patrickab
ID: 18747970
The alternative is that you have two different Open commands:

Open "COM1:12,,0o,7,1" for Output as #1   ' open COM1 port for output
.
.
Open "COM1:1200,o,7,1" for Input as #1   ' open COM1 port for input

Is there a reason for the difference?
0
 

Author Comment

by:bwagner-stl
ID: 18748125
patrickab,

Sorry about the poor typing.  The Open commands are the same accept for the mode...one is for output (so I can send a command to the balance) and the other is for input (so I can read the input from the balance).  Is there an alternate method?  I don't know of an access mode that supports both input and output when a file is not being used.  Also, I'm not sure if a string is being generated by the balance output, but when I execute the input code:

Open "COM1:1200,o,7,1" for Input as #1   ' open COM1 port for input
Input #1, strString   ' get input from balance (weight) and assign it to a string variable
ActiveCell = Mid(strStirng,5,6)  ' parse input
ActiveCell.Select
Close #1   ' close COM1

without first trying to send a command to the balance through the Output code section the number comes into the spreadsheet just fine.  Thanks.
0
Concerto Cloud for Software Providers & ISVs

Can Concerto Cloud Services help you focus on evolving your application offerings, while delivering the best cloud experience to your customers? From DevOps to revenue models and customer support, the answer is yes!

Learn how Concerto can help you.

 
LVL 45

Expert Comment

by:patrickab
ID: 18748325
Will it accept 'Read' as in:

Open "COM1:1200,o,7,1" for Input as #1   ' open COM1 port for input
Read #1, strString   ' get input from balance (weight) and assign it to a string variable
ActiveCell = Mid(strStirng,5,6)  ' parse input
ActiveCell.Select
Close #1   ' close COM1
0
 

Author Comment

by:bwagner-stl
ID: 18755258
patrickab,

Thanks for the idea, but no using the READ statement did not work.  I ended up finding a solution by using the MSCOMM32 Active X component that Microsoft has.  It seems like the key was there has to be some type of small delay between outputing to the balance and reading from the balance.  When I put a delay in of approximately 250 milliseconds the code (using the mscomm32.ocx) works great.

Thanaks so much for your help and prompt response.  I'm kinda new on EE and was wondering is there a way you can receive a partial point count for being so quick to assist me?  If so, how do I go about do that?  Thanks!
0
 
LVL 45

Accepted Solution

by:
patrickab earned 2000 total points
ID: 18755348
bwagner-st,

Glad you solved the problem. Thank you for your kind thoughts but I'm afraid there's no partial points system here - only grades but that doesn't reduce your 'spend' of points. I suggest that as you solved the problem yourself it would be right to ask for the question to be closed and for a refund of your points. It would be worth PAQing (archiving) your result for others to see.

You can ask a free question at the following link:

http://www.experts-exchange.com/Community_Support/

Requesting "The question is closed and points refunded because you've solved the problem yourself - but PAQ for future use."

Quote the URL for your question. In this instance it is:

http://www.experts-exchange.com/Programming/Languages/Visual_Basic/Q_22457880.html?cid=238#a18755258

Hope that helps

Patrick

0
 
LVL 45

Expert Comment

by:patrickab
ID: 19130704
DanRollins,

It seems that the questionner solved the problem himself. Perhaps it's worth PAQ'ing. The points should be refunded.

Patrick
0

Featured Post

Free Tool: IP Lookup

Get more info about an IP address or domain name, such as organization, abuse contacts and geolocation.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Some code to ensure data integrity when using macros within Excel. Also included code that helps secure your data within an Excel workbook.
Access developers frequently have requirements to interact with Excel (import from or output to) in their applications.  You might be able to accomplish this with the TransferSpreadsheet and OutputTo methods, but in this series of articles I will di…
This Micro Tutorial demonstrates how to create Excel charts: column, area, line, bar, and scatter charts. Formatting tips are provided as well.
Excel styles will make formatting consistent and let you apply and change formatting faster. In this tutorial, you'll learn how to use Excel's built-in styles, how to modify styles, and how to create your own. You'll also learn how to use your custo…

572 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question