Keithley 2591 Shaving Milliseconds free download

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A G R E AT E R M E A S U R E O F C O N F I D E N C E Shaving Milliseconds off of Test Time Mark Cejer Business Manager, Keithley Instuments, Inc. Cleveland, OH T HE concept of a test sequencer is urement. Data is then sent from the instru- a significant communications bottleneck by not entirely new. Essentially a ment to the PC where the PC decides wheth- enabling the instrument to communicate di- sequential list of test operations er the DUT (device under test) is in tolerance rectly with the handler. The test sequence is that reside outside the PC, test se- or not. If it is out of tolerance, the PC sends downloaded to the instrument from the PC, quencers have been readily avail- a signal to the handler to reject the part and which is a one-time event. When the device able in higher-end ATE systems that can cost another test can begin. handler places a part into position, it sends upwards of a million dollars. Now, test se- The main problem with this type of setup a signal to the instrument to begin the test. quencers are becoming more common in less is the slow and continuous communication The instrument performs the test, makes the expensive instruments as well. Here's a look of data between the PC and the instrument. pass/fail decision, and sends instructions at how test sequencers can speed up tests on The test sequencer approach, on the other back to the handler. This eliminates the con- optical devices, saving time and money. hand, involves a connection from the PC tinuous transfer of data over GPIB and there- A test sequencer is essentially a sequential to the instrument and from the instrument fore decreases test time. list of test operations that a system performs to the device handler. Eliminating the link In most cases, an improvement in over- on a device. Test sequencers are preloaded from the PC to the device handler removes all test throughput of as little as 10 to 100 into a test instrument, saving the instrument and the device handler from having to com- municate continuously with the PC. This au- Component Handler tomates the test process and shaves precious time off of the test cycle. Digital I/O Mechanical In a typical test setup without test se- Connection quencing, a PC communicates with a test in- IEEE-488 Test Test L