How to Connect Your HPLC Flow Meter to a PC

Accurate HPLC flow rate records not only indicate GMP but are crucial when the FDA comes to call. Digital liquid flow meters such as the FlowCal 5000 support FDA compliance for IQ, QQ and PQ validations in calibrating HPLC pump flow rates.  Connecting these meters to a PC with an RS-232 interface transfers flow meter readings into Excel via the Windows HyperTerminal program.  It is a three-step process whereby data are collected and displayed using HyperTerminl.exe, copied on a clipboard and pasted into Excel for analysis.

Before starting on this project be sure the flow meter is off, otherwise you risk damage to the RS-232 and/or the PC or printer.  Then follow these steps:

First decide which serial (COM) port you are to use on the PC and set it up to the same settings as the flow meter (see below). The gray RS-232 cable supplied with the FlowCal 5000 flow meter will connect directly to most computer 9 pin COM ports. With the flow meter ‘powered down’ connect the RS-232 lead to the computer COM port and to the flow meter. Then power up the flow meter.

The next step is baud rate selection.  As supplied the FlowCal 5000 digital HPLC flowmeter is set up to the default mode as 9600 baud, 8 data bits, 1 stop bit, no parity and “X on X off “ flow control. Instructions provided with the flow meter enable setting to match the printer or computer.

Then set up the PC to the same settings.  If you are using Windows 95/98 or newer versions then use HyperTerminal.exe.  This is located in the Programs/Accessories/Communications/ HyperTerminal folder.  Select FILE —> Open. You will be presented with the ‘New Connection’ window.

Enter a name eg. Flow meter

Select any icon

You will then see the’ Connect to’ window.

Then “connect to:”

Country – USA

Area code – put in your area code (required but not used)

Phone number – (leave blank)

Connect using – change this from the modem default to COM1 or the port you use

Select OK

Choose your port settings:

Bits per second (baud rate): select 9600 to match the default flow meter baud rate

Data bits – 8

Parity – None

Stop bits – 1

Flow control – select X on X off

Click OK

Be sure to save the settings for future use when exiting the program!

When the eluent is flowing through the flow meter, the readings should appear in the HyperTerminal / Terminal window. When data arrive at the PC you can copy and paste the readings into Excel.exe while keeping the HyperTerminal program in the background. From HyperTerminal select the data readings you require by using the mouse or the ‘select-all’ command. From the EDIT menu, select COPY to get the selected data onto the clipboard. Switch back to Excel and paste the data, then proceed with any analysis you may require in Excel.


Is this information useful? How does your lab or manufacturing facility collect and maintain HPLC flow rate records?  What do you find to be the most difficult about fulfilling this important requirement?

About Bob Sandor

Bob began working as a chemist in 1987 and remains a science geek to this day. After his PhD he worked on the bench in materials and inorganic chemistry for 10 years. He then took on a love for marketing and sales. He combined his passion for science and business and took entrepreneur general management positions in large corporations like Hoecsht Celanese now Sanofi Aventis, Bel-Art and Smiths Detection. There he learned what it would take to run a business and finally Tovatech was co-founded in 2006. Bob’s hobbies include playing, listening and composing music, skiing, working out, the internet and all things science. Read More