An automated test system was created
using National Instruments LabVIEW, Intelligent Actuator
motion controllers and stages, Watlow PID heater controllers,
and a network of analog and digital sensors.
A test system was created to automate the
task of controlling and sampling the surface temperature of
the unit-under-test (UUT.) One half of the system (the test
controller) consists of a PC, 4 thermal and motion controllers
and associated power and IO distribution modules mounted
inside a 19” rack. The second half of the system (the test
platform) contains a custom aluminum and Lexan enclosure
housing the motion control stages, thermal monitoring
equipment, coolant distribution, safety interlocks, and the
removable UUT mounting assemblies.
The system was designed primarily for
deployment into a manufacturing environment for use by
semi-skilled operators. An emphasis was placed on simplicity
and safety. In basic production mode, the operator only has
to mount the UUT into the test platform, select start from the
basic GUI and pick the UUT part number from a list box. The
LabVIEW application opens the appropriate “recipe” file and
handles the rest!
A more demanding R&D environment requires
additional capability afforded to those logged in at the
engineer level. The thermal profiler software allows the
engineer to create a wide array of scan patterns, create
thermal set points, and save them to test recipes. Thermal
alarms, time delays, sampling rates, and recipe assignments
are all handled in a separate configuration section. Each
system component can be monitored and controlled in a series
of manual control panels.
The operator selects start, selects the
UUT type and enters the UUT part number. The program loads a
recipe into memory, downloads the thermal set points to the 2
heater controllers, moves the temperature probe to the first
sample point, and enables the safety power relays inside the
test controller. After a configurable delay the program
begins sampling the temperature at each sample point in the
scan pattern. The data is logged to a data file in.csv format
at each sample location. The data file is easy to open and
review using MS Excel or a custom 3D graphical analysis tool.
At test completion the heater controllers are disabled and the
axes are moved back to a designated safe location for easy
unloading and loading of the UUT’s.
