UPS manufacturer cuts testing time

Mechanical Engineering, Nov 1999 by DeGaspari, John

MGE UPS Systems Inc., a Costa Mesa, Calif., electronic component manufacturer, used an 8-bit oscilloscope and a paper recorder in its IR&I) department. Setting up both instruments was tedious and time-consuming, and they often had to be connected to other components such as transformers. As a result, essential data required for testing often could not be captured. Traditional oscilloscopes have low measurement resolution, which at 8 bits or less limits test accuracy. The average memory of most oscilloscopes is 32K, which limits the amount of viewable data for a given event.

To seek a solution, Trent Miller, senior test technician at MGE, specified a DL708 ScopeCorder, supplied by Yokogawa Corp. of America in Newnan, Ga.. The device combines functions of paper chart recorders and digital oscilloscope into one unit. The DL708 offers 12-bit resolution, which increased measurement accuracy.

"It's now very easy for us to measure voltage fluctuations," Miller said. "The new instruments also increased signal accuracy, which gives us a better idea of what is going on in a circuit." The improved resolution, offering 4,096 data points versus 256 points with the old oscilloscope, also gives a better idea of what the signal actually looks like, he added.

The unit has 8 MB of memory, making it possible to monitor longer periods of activity while maintaining a high sampling rate. "This means a higher volume of sampling. If an operator is looking at a time event that takes one second, at 32K he will only get 20,000 data points, whereas with 8 MB five million data points are available." The added memory makes it possible to capture data 10 times faster than the old recorders, Miller added. "We can run it for a long time and see how certain events are happening in sequence, which is very helpful when we test our units."