Alicat VC Series Volumetric Flow Controller User Manual

Page 25

Collecting Data:

The RS-232 output updates to the screen many times per second. Very short-term events can be

captured simply by disconnecting (there are two telephone symbol icons at the top of the HyperTerminal®

screen for disconnecting and connecting) immediately after the event in question. The scroll bar can be

driven up to the event and all of the data associated with the event can be selected, copied, and pasted

into Microsoft® Excel® or other spreadsheet program as described below.
For longer term data, it is useful to capture the data in a text file. With the desired data streaming to the

screen, select “Capture Text” from the Transfer Menu. Type in the path and file name you wish to use.

Push the start button. When the data collection period is complete, simply select “Capture Text” from

the Transfer Menu and select “Stop” from the sub-menu that appears.
Data that is selected and copied, either directly from HyperTerminal® or from a text file can be pasted

directly into Excel®. When the data is pasted it will all be in the selected column. Select “Text to

Columns...” under the Data menu in Excel® and a Text to Columns Wizard (dialog box) will appear.

Make sure that “Fixed Width” is selected under Original Data Type in the first dialog box and click “Next”.

In the second dialog box, set the column widths as desired, but the default is usually acceptable. Click

on “Next” again. In the third dialog box, make sure the column data format is set to “General”, and click

“Finish”. This separates the data into columns for manipulation and removes symbols such as the plus

signs from the numbers. Once the data is in this format, it can be graphed or manipulated as desired.

For extended term data capture see: “Sending a Simple Script to HyperTerminal®” on page 26.
Data Format:

The data stream on the screen represents the flow parameters of the main mode in the units shown

on the display. For volumetric flow controllers, there are three columns of data representing volumetric

flow rate in the units specified at time of order, set point and the selected gas.

+4.123 4.125 Air

+4.124 4.125 Air

+4.125 4.125 Air

VC Series Volumetric Flow Controller Data Format

For mass flow controllers, there are 6 columns of data representing pressure, temperature, volumetric

flow, mass flow and the selected gas. The first column is absolute pressure (normally in PSIA), the

second column is temperature (normally in °C), the third column is volumetric flow rate (in the units

specified at time of order and shown on the display), and the fourth column is mass flow (also in the

units specified at time of order and shown on the display). For instance, if the meter was ordered in

units of SCFM, the display on the meter would read 2.004 SCFM and the last two columns of the output

below would represent volumetric flow and mass flow in CFM and SCFM respectively.

+014.70 +025.00 +02.004 +02.004 2.004 Air

MC Series Mass Flow Controller Data Format