Keithley System Increases Safety, Reduces Cost of Test for Airbag Igniters, Cables, Harnesses, Connectors, and Components.

Business Editors

CLEVELAND--(BUSINESS WIRE)--April 29, 2002

Keithley Instruments, Inc. (NYSE:KEI), the leading producer of automotive airbag igniter electrical test equipment, today introduced its Model 2790 SourceMeter(R) Switch Airbag Inflator Test System.

This automated test system provides the lowest initial cost, reduced test development costs, and highest throughput, resulting in an overall cost of test much lower than existing igniter test systems. This is accomplished by tightly integrating sourcing, measuring, and switching functions in a single instrument, by eliminating the need for synchronization between the computer/controller and the Model 2790, and by reducing signal routing complexity. In addition to airbag igniter tests, the Model 2790 improves test efficiency and throughput in many other applications, such as continuity and hi-pot testing of cables, wiring harnesses, and connectors, plus general high/low ohms measurements on a wide variety of electronic components and materials.

Moreover, the Model 2790's low energy voltage and current sources have been designed to reduce the possibility of device damage while still accurately measuring critical low and high resistance parameters. Additional safety features include a hardware source interlock, and an automatic output cable capacitance-discharge circuit for high voltage insulation resistance testing.

Applications and Markets. The Model 2790 SourceMeter Switch System satisfies the testing requirements for the main passenger and driver airbag inflators and modules, plus those used in smaller ancillary airbags, such as side, seat, foot, knee, and headliner inflatable tubes and curtains. It can be used for both single- and dual-stage inflators and modules, and serves equally well for testing pyrotechnic seatbelt pre-tensioners and related safety systems. Beyond these primary applications, the modular design and flexibility of the Model 2790 make it an excellent choice for automated production testing where programmable high voltage and current sourcing are needed for insulation and continuity resistance measurements.

Application Background. The Model 2790 SourceMeter Switch System is designed for a general class of airbag inflator testing referred to in the automotive industry as 'E-Check' (not to be confused with emissions testing done in many US regions). The primary airbag inflator E-Check is verification of proper electrical characteristics in the pyrotechnic initiator, a fusible wire with a typical resistance of around 2-3 ohms. A second test checks the safety shorting clip (less than 100m(OMEGA)) to verify that initiator pins are shorted together, a safety feature that prevents accidental activation during airbag handling and installation. (The shorting clip is removed after installation is complete.) A third test is a high voltage isolation resistance measurement to make sure there is no electrical leakage path (i.e., low resistance) between the initiator and the grounded metal housing of the system's electronic module, which otherwise could cause a "no-fire" condition. Some manufacturers perform additional electrical tests on their airbag modules and wiring harnesses using the same E-Check test stand.

Airbag module manufacturers face severe pricing pressures and produce in high volumes, so production testing solutions must provide both high throughput and high quality testing. Furthermore, recent advancements in "smart" airbag systems have increased the number of initiators per airbag and number of inflator devices per vehicle, thereby intensifying the need for cost-effective, flexible, and integrated test solutions. By supplying a complete test solution with a modular architecture, the Model 2790 supports single and dual inflators, single and dual test stands, and even hybrid applications such as steering wheel modules that require a combination of inflator and ancillary device testing. The combined signal switching, source, and measurement capability of the Model 2790 enhances test throughput even more by allowing parallel high voltage soaks, and accommodates multiple head test stands that improve operator efficiency and minimize idle time.

Product Details. The Model 2790 SourceMeter(R) Switch System is a complete low cost solution for automated "Hi-Lo" resistance testing using either four-wire or two-wire measurements. It consists of a digital multimeter (DMM) mainframe for measurements, with two expansion slots for source/switch plug-in modules.

Four main system variations are available:

-- 7751 High Voltage (HV) Source/Switch Module: Includes programmable current
and high voltage sources, I-V and V-V signal conditioning, four channels of DUT
switching, and automatic cable discharging for a complete inflator E-Check
solution.

-- 7752 Source/Switch Module (no HV): For ancillary low ohms measurements. The
switch configuration is four channels on one Form A switch, and eight channels
as four four-pole or eight two-pole connections for routing four-wire signals
into the DMM or I/V converter.

-- 7702 40-Channel Differential Multiplexer Module: When combined with a 7751
or 7752 module (2790-H or 2790-L), enables up to 40 channels of two-wire
programmable 50-500V Source-V high resistance testing (w/7751) or 20 channels
of four-wire programmable 0-50mA Source-I low resistance testing (w/7752), plus
access to all DMM mainframe functions (except thermocouple measurements).

Source/Switch Modules:

-- 7751 High Voltage (HV) Source/Switch Module: Includes programmable current
and high voltage sources, I-V and V-V signal conditioning, four channels of DUT
switching, and automatic cable discharging for a complete inflator E-Check
solution.

-- 7752 Source/Switch Module (no HV): For ancillary low ohms measurements. The
switch configuration is four channels on one Form A switch, and eight channels
as four four-pole or eight two-pole connections for routing four-wire signals
into the DMM or I/V converter.

-- 7702 40-Channel Differential Multiplexer Module: When combined with a 7751
or 7752 module (2790-H or 2790-L), enables up to 40 channels of two-wire
programmable 50-500V Source-V high resistance testing (w/7751) or 20 channels
of four-wire programmable 0-50mA Source-I low resistance testing (w/7752), plus
access to all DMM mainframe functions (except thermocouple measurements).

A dry circuit, low ohms function clamps the source voltage at 20mV maximum for shorting clip tests at currents up to 1mA. The multimeter mainframe functions provide 6-1/2-digit precision in DCV measurements from 1uV to 1000V, DCI measurements from 10mA to 3A, resistance from 100u(OMEGA) to 100M(OMEGA), and temperature using an RTD or thermistor, plus various AC measurements.

Price and Availability. Keithley Model 2790 SourceMeter Switch Airbag Inflator Test Systems are available immediately, with prices ranging from $4995 to $7995, depending on model selected.

For More Information. For more information on the Model 2790 or any of Keithley's test solutions, contact us at:

         Telephone:            888-KEITHLEY
                               (888-534-8453)
                               440-248-0400
         FAX:                  440-248-6168
         E-mail:               [e-mail]
         Internet:             www.keithley.com
         Address:              Keithley Instruments, Inc.
                               28775 Aurora Road
                               Cleveland, OH 44139-1891

About Keithley Instruments. Keithley Instruments, Inc. provides optical and electrical measurement solutions from DC to RF (radio frequency) to the telecommunications, semiconductor, optoelectronics, and other electronics manufacturing industries. Engineers and scientists around the world use Keithley's advanced hardware and software for process monitoring, production test, and basic research.

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