Dr. KnowAgilent offers the ADM Flow Meter (G6691A) with replaceable calibrated cartridges. The Flow Meter has a black-and-White digital display and works with acoustic displacement measurement.
The firmware can be updated by connecting the ADM Flow Meter to a computer via its microUSB port. Before this works, a driver needs to be installed that is available online as described in the manual.
The USB port then emulates a serial COM port. With terminal programs like HyperTerminal or PuTTY, this serial port can be read, and the flow registered. Seeing it more comfortably and logging the results was not easily possible.
I wanted to do just that, have a nice flow display on the computer screen with a graphical representation, and log flow values from time to time.
As we all have Office 365/Office 2016 on our computers, it was an option to use one of these programs for the data acquisition. I chose MS-Access 2016 as I wanted to log data in a database. MS-Access can be programmed in Visual Basic for Applications (VBA) and I was familiar with it.
The tool now comes as a compiled database file, ADMFlowmeter.accde or ADMFlowmeter_64.accde and a double-click starts it in MS-Access 2016/MS-Access 2019, immediately the tool checks all serial ports and tries to find the one the flow meter is connected to. If it doesn't find it, you still can choose the right port yourself.
And that's how it looks like:
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The drop-down field lets you choose the serial port COM1 to COM8.
START and STOP will control the reading from the flow meter and the flow, and the time and date will be shown in the appropriate fields.
START LOGGING will start the data logging to the internal table/log file approximately twice a second, the last 60 seconds will be graphically shown in the graphic window. The raw input from the flow meter will also be shown in hexadecimal format in the bottom field.
Pressing the red button will empty the log file, pressing the orange button will show the log file and pressing the purple button will export the log file to Excel (XLS) format.
A log file looks like:
The blue buttons will direct you to the PC Connection manual online or the site to request a Certificate of Calibration. |
If someone without Office 2016 wants to run the tool a MS-Access 2016 Runtime version can be downloaded free from the Microsoft Download Center. Please read if the runtime library is compatible with your computer system, installation is done on your own risk.
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Changes in the 64bit version:
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Do It Yourself:
If you want to read out the instrument yourself with any terminal program, connect with 9600 8N1 (9600 baud, 8 bit, No parity, 1 stop bit). Read data until you get 0A0D (bytes are representing the ASCII codes of {[0..9], CR, LF, BLK, ".", "-"}), that's it. An example is the hex sequence below the first figure:
| 0A | 0D | 20 | 36 | 2E | 36 | 32 | 32 | 38 | 20 | 0A | 0D |
| LF | CR | BLK | 6 | . | 6 | 2 | 2 | 8 | BLK | LF | CR |
with LF = Line Feed, CR = Carriage Return, BLK = Blank. Be aware the flow meter sends LF/CR and not CR/LF or LF alone!
Resources:
- Agilent CrossLab CS ADM Flow Meter Operation Manual
- Agilent CrossLab CS PC Connection User Manual
- Achieve accurate and repeatable gas flow meter measurements
- ADM Flowmeter Certificate of Calibration Addendum
