Engineers know when to automate

Intangibles may make the decision to automate easier or harder.

Martin Rowe, Senior Technical Editor -- Test & Measurement World, 8/1/2011 12:00:00 AM

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The decision to automate product testing often involves more than monetary costs. Indeed, you can start the decision-making process by calculating the time that automating a test can save. A simple calculation comparing the time savings to the automation development time can tell you how long the payback period will be. But intangibles may make the decision to automate easier or harder. Recent discussions on online test-engineering forums pointed to several factors that go into the decision.

Automation improves repeatability over manual testing. Software will configure test instruments and devices under test the same way every time. Software also automates data storage for record keeping and analysis. Manual data entry can introduce recording errors.

Chris Chambers, principal at Touchstone Automation, told me that anytime you have repetitive test operations, you should automate. That goes for engineering evaluations as well as production tests. You’ll also achieve future savings, he said, because “If you automate, you’ll likely develop code and user interfaces that you can use in other projects.”

You also need to consider the maintenance costs for an automated system, particularly if the test station has a long life expectancy. For example, the same equipment models may not be available if you need replacements or if you need to build an identical test station years later. The inability to get replacement equipment may force you to write new code or modify test procedures, both of which can introduce unforeseen errors.

The benefits and costs of automation may not be obvious at first. “If a automated test doesn’t save much time,” said Ken Roberge, senior test engineer at Crystal Technology, “then you can assume an automated test isn’t worth developing.” But he explained that there’s an opportunity cost savings from automation. “The test operator or technician may be able to perform other tasks while an automated test runs,” he said. The time an automated test frees for other tasks, then, may make it worth developing, but only if your management understands opportunity costs.

In some companies, the decision to automate may come down to whether you have a test-equipment budget or whether management looks at cash flow only. For example, suppose that automating a test process requires a $10,000 piece of test equipment. If you buy the equipment, the company will have spent $10,000 in addition to salaries. With manual testing, the company “saves” $10,000.

In some situations, you might actually have to make a case for not automating a test procedure. If an automated test cuts a 30-min test by 5 min, then automating may not be worthwhile. Situations like that may occur if a test has a long setup time or you must perform a manual calibration before each test.

In some instances, automation may not fully replace manual testing. Roberge pointed out that tests may be partially automated; for example, you may use a computer to acquire data from an oscilloscope, but only after you manually tune items such as coils. Similarly, Chambers described an application that required an LED to illuminate at the proper time before a test could complete. Verifying the illumination was a difficult task to automate, so a test operator checked the LEDs. T&MW

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