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serialcomms
Copper Contributor
Aug 17, 2022

Serial COM Ports in Excel VBA

Hello all,   I've uploaded a new set of VBA functions for anyone still interested in using Serial COM Ports with Excel.    GitHub - Serialcomms/Serial-Ports-in-VBA-new-for-2022: Using Serial COM ...
Excel
Macros and VBA
serialcomms's avatar
serialcomms
Copper Contributor

LeoKing 

 

Hello and thanks for your interest in SerialComms VBA.

 

You may have a timing problem between VBA and your instrument. 

 

Modern PC is simply far too fast for relatively slow serial ports and attached devices.

 

Try adding a delay between starting the COM port and sending the Start Sampling command. 

 

Add a second delay between sending the command and waiting for a response.

 

There's an example function at the end of the listing below which shows how to do that. 

 

Serial-Ports-in-VBA-new-for-2022/SERIAL_PORT_VBA.bas at main · Serialcomms/Serial-Ports-in-VBA-new-for-2022 (github.com)

 

Regards,

 

SerialComms

 

Andrew_M395's avatar
Andrew_M395
Copper Contributor
Jan 06, 2024
It is great that you have provided these functions. However I am having a similar issue talking to an Arduino. Neither the example() or the ..open, ..transmit, ..receive in a subroutine work. However if I run the functions in the immediate window, then it does work. If I insert breakpoints on my subroutine at each function then again it does work. However if I add delays using either sleep() or the waitcomport() function it does not work. If I step through the breakpoints too fast in my subroutine I can get it to not work, so it is clearly a time related issues, but I cannot see why the delays within example() or the delay in my subroutine do not work for me.
Regards Andrew Mellon
  • Andrew_M395's avatar
    Andrew_M395
    Copper Contributor
    Jan 06, 2024
    I have solved this: I needed to add a delay between the open port and transmit in my own subroutine. This despite the fact that the transmit reported sending the data sucessfully. I then went back to the example and invcreased the delay before If Port_Started(Port_Number) Then to 2000 and it worked.
    Thanks again for the code.
    Regards Andrew M
    • serialcomms's avatar
      serialcomms
      Copper Contributor
      Jan 07, 2024

      Andrew_M395 

       

      Hello,

       

      At least one Arduino model (Uno R3) will intentionally reboot when a serial connection is made to it. This may explain the need for a delay after opening the port as you have discovered. 

       

      The following Github repository contains a modified version which allows an Arduino serial connection to be made without rebooting it. 

       

      Serialcomms/Serial-Ports-in-VBA-Arduino-2023: Arduino R3 serial version (github.com)

       

      There is also a separate function to reboot the Arduino if you need it, and a sample Arduino sketch to send analogue channel values to the serial port. 

       

      Note also that the Uno is relatively slow compared to a modern PC which further increases the need for timing delays. 

       

      Regards,

       

      Serialcomms.

      • Andrew_M395's avatar
        Andrew_M395
        Copper Contributor
        Jan 08, 2024

        serialcomms  Thankyou for the help it was useful. I should have realised by Arduino was rebooting on connection.  It explains some other things I did not understand happening.  First use of Arduino.  I will certainly look at the Arduino version.  

        Thanks Andrew M

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