Sigma Microsytems is a AS9100 Rev D certified company, by NQA USA, accredited to UKAS |
Test Systems |
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Every embedded system, sub-system or module needs to be tested to various degree independently, before being deployed for field installation / integrated with other entities. After basic testing in the design and development phase is completed, there is a need to test the unit as a black box, by feeding simulated input signals and monitoring the output signals for verifying expected behavior.
Test systems designed for specific testing needs of embedded units may be of different types:
In general, the test jigs provide a set of input signals to the Unit UnderTest (UUT), as per specifications, thereby simulating the field signals / environment. The output signals provided by the UUT are monitored by the Test Jig, and compared with predetermined / expected values, with suitable tolerance.
Sigma has designed, configured, manufactured and deployed various types of test systems to address specific testing needs of various embedded units.
PC basedTest Systems
![]() PC based systems typically employ a set of add-on cards, which provide the required signals (typically analog, discrete and pulse). These signals are fed to the UUT. Similarly, signals from the UUT are also monitored by connecting them to suitable PC add-on cards.
This approach of
testing may be carried out either using the existing application
software on the UUT or by specially writing a diagnostics software on
the UUT. Usually the later approach facilitates a more detailed test /
diagnostics, unless the application software itself sufficiently caters
to Built-in-Test (BIT) and diagnostics.
As an extension of the above concept, it is possible to use a communication card, to cater to interfaces like MIL-STD-1553, ARINC-429, ARINC-573, ARINC-717 or even simple serial ports. Using a GPIB card enables usage of standard Test and Measurement (T&M) equipment like power supplies, oscilloscope, spectrum analysers and signal generators to test the UUT, under the overall control and test philosophy adopted on the PC based Test System. Sometimes, it is also necessary to generate complex waveforms and timing-critical signals for the UUT. Such requirements are usually addressed with custom-designed add-on cards, usually based on FPGA / CPLD devices. PC based test systems may be typically configured with:
Each of the above configuration addresses specific testing needs and has its advantages and disadvantages. While compact PCI / PXI offers very reliable performance, it is considerably more expensive, compared to desktop PC or even industrial PC configurations. Industrial PC configuration offers a good trade-off between reliability and cost, while desktop PC offers the most cost-effective solution for lab environment Configuring a test system, besides the selection of the platform and overall configuration, involves the selection of individual boards:
PC based Test System offers the following distinct advantages:
Software solutions for PC basedTest System include:
Sigma can provide solutions on both approaches.
EmbeddedTest Systems, with PC connectivity
Certain
applications need to use an embedded test system for reasons like
portability, signal timings, power consumption and such other factors.
Such test systems usually comprise of an embedded processor-based
board, with custom test software. The test system then simulates the
I/O signals for the UUT.
The test system usually initiates tests, under the supervisory control of a PC host. Test inputs and results may be transferred between the PC host and the embedded test system. Usually these type of test system features some basic local display and control, so that limited tests may be carried out without PC connectivity. Standalone Test Jigs
Standalone
test jigs are used for basic testing, using local controls like
potentiometers, panel meters, switches, LED's and test-points. These
jigs are typically non-intelligent, low-cost and usually meant for
simulating and monitoring simple signals. It is quite suited for
board-level testing and basic trouble-shooting / debugging, and usually
very economical and cost-effective.
SUPPORT
Long-term
support of Test Systems is an important factor, as we need to take into
account the support path, vis-a-vis the obsolescence factor. In case of
PC based platforms, it is possible to upgrade to higher processor
modules, while retaining the same configuration for the rest of the
system, with minor software changes, if any. However, engineering
constraints like thermal dissipation needs to be addressed. While
designing custom boards, we exercise caution such as component
availability period, availability from multiple manufacturers /sources,
and such other factors.
Some of the Test Systems designed, configured, manufactured, supplied and commissioned by Sigma include:
1. Test Rig for SSFDR Jaguar Compact PCI 7. VOR/ILS Test System Industrial PC 8. OBC Simulator Desktop PC
Above
PC based Test systems feature a combination of COTS boards, custom
designed add-on cards and signal-conditioning cards. Test software is
custom-developed with GUI and ActiveX controls, on MS Windows platform.
Test software is provided with fully IV&V certification, with
fully-fledged software documentation and exhaustive test reports. Test
systems are cleared by respective certification agencies, including
RCMA and DGAQA.
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