Study shows major jump in precision measurements

Cleveland, Ohio-Plant and process control engineers will be taking more measurements with higher precision in the next few years, and they will be looking for new communications methods for collecting those measurements, according to a recent survey commissioned by Keithley Instruments.

Consumers today demand products of unparalleled quality and reliability, and manufacturers are responding by demanding their suppliers provide components produced with six-sigma quality levels while maintaining tremendous cost controls to drive the prices of those components down, the report observes.

Meanwhile, company executives are demanding that their manufacturing managers operate in an environment often characterized by breakneck output goals and the need to be compliant with global standards such as ISO and the CE mark, says the study, which Keithley commissioned to quantify the effects of several trends affecting industrial measurement.

"Driven by these increased customer needs, the factory floor is certainly becoming a far more controlled and demanding environment," said Michael Minneman, a Keithley product general manager. "Engineers are subjecting their processes to tighter monitoring and controls, seeking to measure parameters that only a few years ago were viewed as low priorities. Today, it seems, everything is a priority on the production line."

The survey, conducted in September 1996, included responses from 199 production engineers. Participants were asked to answer a series of questions based on the following statement:

"Consider a single production line in your plant today and answer the questions below as they apply only to that individual line, rather than your entire facility."

Nearly a third of respondents measure more than 40 sensor points or electrical parameters on a single production line in their facilities, with one out of five monitoring more than 100 points on a line. Interestingly, 57% said they envisioned the number would increase in the next two years.

When respondents were asked to describe "their most demanding measurement," engineers see their measurement needs increasing significantly during the next few years. Seventeen percent of respondents forecast they'll need more than 18-bit resolution two years from now, three times the number who require that level of performance today (4.3%).

The need for high-speed measurements of 10,000 readings per second and higher will also grow nearly threefold in coming years, they said, with the 5.9% reporting that level today expected to increase to 16.5% in the future. Most dramatic is the need for accuracy, the study said, with nearly a third (32%) today who need accuracy at least .1 % of full-scale range or better booming to nearly half (47%) in the future.

When asked to rank the most important barrier to achieving the level of measurement needs today, one out of five pointed to current levels of instrument hardware performance, followed by sensor performance. Other key factors cited included internal financial resources (14.5%) and the time-consuming nature of system configuration (13.8%).

Nearly three-fourths of survey respondents use serial port connections to capture measurement data today, followed by 4-20 mA (64.5%), then Ethernet and IEEE-488, both at 39%.

However, most users expressed only moderate satisfaction with their communications solutions. When asked to express their satisfaction on a scale of 1-5, with 5 being very satisfied, the most common protocol used, RS-232/422-485, also scored the greatest dissatisfaction ranking, at only 2.5 out of 5.0. The 4-20 mA protocol, also one of the more widely used solutions along with Ethernet, also scored relatively low in satisfaction, 2.72 out of 5.0. IEEE-488, the standard among instrument users, scored only 3.35 in satisfaction among these industrial respondents.

Ethernet is currently the centralized data communication network of choice in the factory, with nearly 60% of respondents identifying their plant's centralized data network as Ethernet, the study indicated.

However, here again dissatisfaction with current solutions seems widespread. Only a third (32.2%) said they would "continue to use this network for measurement data gathering and reporting in the future," if they were given a choice.

"Production in the 1990s is a far different place than even a few years ago, driven as much by external changes as by new technology," said Minneman.

"Our customers tell us that the demands for throughput, quality, and standards compliance are dramatically changing the scope of the measurements conducted in factories today.

"We seem destined to face a proliferation of networks for the foreseeable future," Minneman noted. "Nearly half of those participating in this survey reported that their facilities have not yet selected a standard data network; 44% of those couldn't even foresee standardization on the horizon."

A full copy of the survey and its results are available from Keithley Instruments: phone: 800/552-1115 or 216/248-0400; fax: 216/2486168; e-mail: product_info@keithley.com; Internet: http://www.keithley.com.

Copyright Instrument Society of America Jan 1997
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