Why precision matters for modern ATE systems
When purchasing new automated test equipment (ATE), you want to invest in tools that produce repeatable, reliable measurements over time. In other words, you’re looking for precision.
While accuracy and resolution are often the first things you’ll see on a spec sheet, precision can be the deciding factor to make or break an ATE system. With high precision, you’ll get consistent results that lead to greater throughput and less downtime. Compare that to legacy systems, which are often less precise by today’s standards and can cause bottlenecks in the measurement process due to frequent breakdowns and slow measurement times.
Here, we’ll explain how precision can lead to better results in the lab and why it should be part of your consideration when upgrading ATE equipment.
Precision vs. accuracy
Precision isn’t just a general term to describe high-performance measurement equipment. It has a specific meaning that relates to another term: accuracy.
Accuracy describes how close a measured value is to the accepted or reference value, while precision describes how consistently an instrument repeats a measurement under the same conditions. In instrument specifications, accuracy is expressed as an allowable error under defined operating conditions. While industrial multimeters are often specified as a percentage of reading, high-performance reference instruments are specified in much tighter terms, such as ±ppm of reading or µV/V.
The Fluke 8588A Reference Multimeter, for example, is specified at ppm-level DC voltage performance, including 2.7 µV/V one-year relative accuracy at 95% confidence.
Precision, or repeatability, is the ability to produce closely agreeing results when the same measurement is repeated under the same conditions.
The bullseye model
A bullseye or target is a common way to describe the relationship between precision and accuracy. If you shoot at a target several times and hit the same area on the outside rings, those shots would be precise, but not accurate. That’s because you produced the same result several times (precision), but shot too far off from the bullseye, resulting in a high degree of error (accuracy). However, if you hit the target dead center several times, that would be a mark of both high precision and accuracy.
When a tool has both high accuracy and high precision, that means it can take measurements with minimal errors and produce the same results time and time again. For modern ATE systems, improved accuracy and precision have a domino effect on test throughput, maintenance costs, and uptime.
Benefits of increased precision
Many labs still rely on legacy test equipment to power their ATE systems. While it may seem cost-effective to keep equipment in use for as long as possible, legacy tools can cause expensive headaches over time.
Older components typically need more maintenance and are prone to costly breakdowns as they age. That can lead to process bottlenecks, making backlogs and delays more common. Less precise machines also mean that results are less repeatable, leading to frequent re-testing that can take up more time.
But teams that prioritize modern precision in their ATE systems experience:
- Increased throughput. Precise measurements mean repeatability and consistency. These factors make it easier to get through backlogs quickly, since you don’t have to second-guess measurement results or re-test devices.
- Faster results. Modern precision measurement tools automate many of the processes that formerly needed to be done by hand. And with automation built into the process, they eliminate the possibility of human error, leading to higher accuracy.
- Fewer maintenance costs. Repairs on legacy equipment add up quickly. But with newer precision measurement tools in your workflow, there will likely be fewer emergency breakdowns and routine repairs.
- Less risk. Teams that base decisions on reliable, repeatable measurements take fewer risks, preserve product integrity, and maintain customer trust. Your bottom line is too important to gamble with, and precision measurement makes it easier to build reliability throughout the lab and beyond.
- Better compliance. Technicians in highly regulated industries need confidence that products and equipment meet required measurement standards. Precise and accurate ATE devices reduce system-level uncertainty, ensuring that teams can meet compliance benchmarks.
If your measurement tools are several decades old, it’s likely that you’re missing out on performance improvements that can make testing faster and more precise. Precision and accuracy standards have greatly improved over the past several decades. The Fluke Calibration team witnessed this firsthand after replacing legacy multimeters with the 8588A Reference Multimeter at their lab in Everett, Washington.
Case study: how increased precision helped the Fluke team clear backlogs and boost throughput
After accumulating a sizable backlog of customer orders, Fluke Calibration metrologists investigated their workflow and equipment to locate bottlenecks.
Their legacy measurement station featured a Keysight 3458A 8.5-digit Multimeter, which worked quickly but did not provide the accuracy needed to measure more modern tools. At their advanced measurement station, a Fluke 8508A 8.5-digit Reference Multimeter could take more accurate measurements but lacked the speed necessary to keep work from piling up.
So, they decided to swap the 8508A with an 8588A Reference Multimeter. The 8588A features better speed, accuracy, and precision specifications than the 8508A, which quickly made a difference for the Fluke Calibration team.
It took the metrologists eight hours to calibrate a single 55XX series calibrator with the 8508A. The 8588A, on the other hand, sliced calibration time in half for a duration of only four hours. Now, the team is running 95% on time with customer orders, having eliminated the backlog that prompted the upgrade in the first place.
Read more here about how the 8588A helped improve throughput and cut backlogs at Fluke Calibration.
How to locate precision on a spec sheet
Unlike accuracy, precision doesn’t have a singular measurement that you can find in device specifications. Instead, you’ll have to take several factors into consideration:
- Resolution, or the level of detail an instrument can display in a single measurement. Higher measurement resolution means results can be more granular, which improves precision.
- Stability, which reflects the amount of time a device can maintain accuracy before it begins to drift. Instrument drift can introduce uncertainty and errors that impact precision over time.
- Noise, or the extraneous signals picked up during electrical measurements. Noise occurs due to random electrical fluctuations and can distract from the signal you are trying to measure. High-noise environments introduce uncertainty into a final measurement, making it difficult to maintain precision.
Fluke specializes in low-noise, high-stability, and high-resolution test equipment for lab environments. Our customers trust Fluke reference multimeters like the 8588A to help with applications like research and development (R&D), quality control, and precision calibration.
How the 8588A brings precision measurement to the lab
With the 8588A Reference Multimeter, you have a tool on your side that continually produces reliable and repeatable results. High measurement quality builds a bedrock of trust into your workflow, which translates into increased throughput, lower risk, and better compliance.
The 8588A is a low-noise and high-stability reference standard with 8.5-digit resolution for precise measurements. Plus, it comes with features like emulation mode, which helps teams easily slot the 8588A into legacy ATE workflows.