Hardware Reference
In-Depth Information
Figure 12.11
Backup battery load test application written in Visual Basic
this application so the hardware interface is required to be external and available
for fitting to any one of several bench PCs in the production test laboratory.
Hardware
This application makes use of the Measurement Computing PMD-1208LS USB
Personal Measurement Device. This device (see Chapter 2) has four differential
or eight single-ended analogue input channels and is easily moved from one PC
to another. Screw terminals permit connection of test leads and no further
adjustment or configuration is necessary other than ensuring that the software
is loaded and appropriate Measurement Computing library is installed on the
host computer.
Software
The software was written using MS Visual Basic (see below) and the application
is shown in Figure 12.11. A combo-box provides a means of selecting the
sampling rate (from 10 ms to 100 s) with buttons provided to start and stop the
load test. A virtual LED and text field provides status indication. When the stop
button is operated data is sent to a data file in a format that can subsequently
be imported into MS Excel (see Figure 12.12).
'============================================================
' Name: loadtest
' Purpose: collects backup battery voltage data
' Library calls: cbAIn%() and cbErrHandling%()
' Hardware: PMD-1208LS USB HID
'============================================================
Const BoardNum% = 1
' Board number
Dim Index As Integer
Dim Record As Integer
' Dimension data array
Dim data_array(10000)
Dim Gain As Integer
