Development time reduced
March 1st 2009 "Because the development time for new products has been considerably reduced,we no longer need to send prototypes to European test institutes, which has reduced our
development costs," comment Paul McEntee and Boris Bauer - Thermomax
Thermomax is a leading manufacturer
of premium quality equipment for
efficient and economical conversion of
solar radiation into thermal energy. Our
evacuated tube solar collectors are used to
produce clean energy for domestic and
industrial hot water, space heating and
cooling and seawater desalination. At our
manufacturing facility in Bangor, Northern
Ireland, we have installed two new test
facilities one for outside tests under real
conditions and an indoor solar simulator. The
new facilities have significantly reduced the
time and cost of product development and
are useful tools for ongoing production
quality assurance. Using the solar simulator,
we can perform tests all year round, no matter
what the weather conditions are outside.
Building a system
We built two PC-based, fully automated test
systems using FieldPoint-based
hardware and software,
including NI FP-1601 network
modules, relay, counter/timer,
analogue input, output and
thermocouple modules, and
NI LabVIEW DSC and
LabVIEW software.We also
included a two-axis motion
system controlled by an NI
PCI-7342 motion controller
and an NI UMI-7772
interface using LabVIEW.
We employed six FP-1601
network modules on the
outside test rig controlling and
acquiring data from 212
channels. Due to the high channel count, we
employed the LabVIEW DSC Module to
reduce the development time for the control
and data acquisition system and store the data
in an easily accessible database.We can test up
to four collector systems at any one time and
subject them to one of nine test sequences.
We employed an additional FP-1601
network module on the solar simulator to
acquire and control 34 channels.We used the
two-axis motion system to acquire an
irradiance map of the simulator lamp array
prior to each test.We used a LabVIEW
program to perform all the control, data
acquisition and analysis enabling automated
efficiency tests on the collectors to BS EN
12975.We had overcome a unique range of
challenges at each test facility. On the outside
test rig, we had a large number of channels to
deal with and data had to be recorded over
months and even years. In addition, if the
energy from the collectors was not used, they
could become extremely hot.As a result, we
incorporated alarms and safety interlocks into
the system.We used the LabVIEW DSC
Module, which made the design and
implementation of the control system relatively
straightforward.We used the tag configuration
editor to interface with the FieldPoint channels
via the Ethernet to considerably reduce the
amount of code writing.Using the tag
configuration editor, we easily implemented
channel scaling, deadbanding and alarms. The
NI Measurement and Automation Explorer
(MAX) software also proved to be extremely
useful. During commissioning, we used MAX
for low-level control of the FieldPoint
hardware without having to write any code.
When the system runs MAX, it provides a
simple way to view and export data from the
citadel database using the historical viewer.
On the solar simulator, we had a much
smaller number of channels, but the test
requirements of BS EN 12975 demanded
precise control of the temperature and mass
flow rate of the system fluid. To achieve this,
we installed two Honeywell control valves,
one to control the coolant flow to a heat
exchanger for temperature control and the
second to control the mass flow through the
collector under test.We used the advanced
PID VIs in LabVIEW to generate the control
signals to the valves via a FP-AO-V10 twochannel
analogue output module.
Using the advanced PID VIs, we
implemented bumpless manual to automatic
and automatic to manual control. Our second
challenge was to develop a two-dimensional
mapping system to precisely measure the
incident irradiance on the collectors prior to
each test. Initially, we attempted to acquire the
map manually, but this required two operators
and a significant amount of time. As a result,
we decided to install a two-axis motion system
to move the pyranometer and record the
irradiance.We used an NI PCI-7342 motion
controller and an NI UMI-7772 motion
interface to control two stepper drives and
motors. The system moved a Kipp & Zonen
CM11 pyranometer, which is connected to
an analogue input channel on the FieldPoint
bank, and records a 200 point map.
Results using NI products
By using NI hardware and LabVIEW software
a completely integrated solution could be
constructed quickly and easily. The two test
facilities have proved to be very successful
and are in use daily. Because the development
time for new products has been considerably
reduced, we no longer need to send prototypes
to European test institutes, which has reduced
our development costs. The systems were
instrumental in reducing the time to market
for our new range of collector manifolds.We
continue to expand the range of applications of
the systems to quality control and marketing.
In addition, our customers can view real-time
testing of their products via the Web. More articles from National Instruments UK Limited: | 
