User manual

MCP3421 WEIGHT SCALE
DEMO BOARD USER’S GUIDE
 2010 Microchip Technology Inc. DS51918A-page 15
Chapter 3. Weight Scale PC Software Tool
3.1 SOFTWARE INSTALLATION
The Weight Scale PC software is an executable file that does not require installation.
But, to enable running the software, the user must first install two additional programs,
in the following order:
- NI LabVIEW Run-Time Engine
- NI-VISA Run-Time Engine
These programs can be downloaded from www.ni.com
.
3.2 SOFTWARE OVERVIEW
The MCP3421 Weight Scale Demo Board includes a PC graphical user interface (GUI),
that can be used to evaluate the weight scale accuracy and weight scale calibration.
This board is communicating with the software via USB port.
The following figure shows a sample of the software’s GUI in Measurement mode:
FIGURE 3-1: MCP3421 Weight Scale Demo Board Software – Measurement Mode.
The user can control the size of the X axis by writing the desired figure in buffer length.
Several series of statistical analysis are performed on this buffer, the most important
being displayed on the screen, under the Measurement Standard Deviation. This
deviation is measured in grams and represents the RMS noise value of the weight
scale. The actual accuracy of the weight scale can be defined in many ways, but most
commonly it is 10 times the standard deviation.