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ScopeMeter® test tools are 20 years old

By Chuck Newcombe

September 2011

Personal Protective Equipment (PPE) protects electrical workers.

The ScopeMeter 190 Series II development team simulated harsh environments to make certain the sealed case could protect the instrument.

In the late 1980s there were several manufacturers of oscilloscopes. Fluke wasn’t one of them. That was when we were approached by a European company that offered its battery-powered portable ’scope for us to market under our brand.

We took a serious look at the unit and quickly concluded that it came up short on safety and reliability. And the user interface was confusing, to say the least. We rejected the offer, but soon decided to launch our own development program to design a portable oscilloscope and address the shortcomings we had uncovered.

At the time we were in a marketing partnership with Philips, another European company that had development labs in the Netherlands. And, over the next year or so, engineers from both companies worked together to come up with what would become the first ScopeMeter® products - the 93, 95, and 97.

Engineering ping-pong

The collaboration was an interesting one. Philips had sophisticated chip technologies that could be applied to the project, and there was, of course, the eight-hour time difference between their workday and ours. That allowed the engineering team in the Netherlands to complete their workday and send the results to our Washington State offices, where our engineers picked up the ball and performed their tasks while the Europeans slept. I can’t say that the project went twice as fast, but it was a pretty efficient process.

Those first products were portable two channel devices that could be handheld. They had a bandwidth of 50 MHz. And, as their name suggested, these new tools incorporated both oscilloscope and digital multimeter (DMM) features. The three models were introduced in 1991.

Perhaps the most popular ’scope feature of the new units was “Auto Set.” After connecting to a source of electrical signals, simply pressing this green button launched the ’scope into a mode where it automatically selected voltage sensitivity, sweep speeds, and triggering to provide a stable waveform on screen. And, as a DMM, the meter record mode performed similar to a normal DMM’s Min-Max mode, displaying four large digital readings, including Min, Max, Average and present values of True RMS voltages up to 25 MHz. The unit also sported other DMM features, such as the ability to read dc voltages and ohms values.

The top-of-the-line model 97 had extensive memory features - including the ability to save complex instrument setups and recall them to instantly return to an often-used configuration.

The importance of floating measurements

Early in the life of these first ScopeMeter tools, I recall taking one to the development labs for a motor drive manufacturer in Georgia, where I saw a 50 hp adjustable-speed motor drive being tested using line-powered bench oscilloscopes, electrically isolated using isolation transformers for power, and rubber mats for their carts. This was necessary because the tests being performed were not ground referenced, while the scope inputs were. The tests had to be set up while the drive was inactive, and then test results observed when power was restored. The technicians had to be careful not to touch the oscilloscope because of the floating high voltages.

Imagine the engineers’ surprise when I handed them the 97 ScopeMeter test tool, instructing them on its operation in a fully isolated battery powered mode using the 10:1 input probes. The critical test was the ability to read the sub-microsecond rise time of the floating PWM waveforms, which the 97 did with little effort, while held in the technician’s hands.

Going beyond the 97

Not too long after, I again dealt with a customer who wanted to go a little beyond what the 97 had been designed to do. You can read about our work-around to trigger on high-frequency transients here:

Read “Extend your reach: Create a high-pass filter” »

The last 20 years have seen steady progress and improvement in the ScopeMeter family. The original 90 Series was improved, with bandwidth extended, in the 105. Then simpler and less expensive models were introduced, as represented by the 120 Series, in the late 1990s. All of these models had two channels, but used a shared common reference.

The 190 Series was introduced in 2000, again with two channels, but now with full electrical isolation between the channels, making connections much simpler and safer. These units, like all previous ScopeMeter products, used an innovative gray scale presentation in the display to highlight features of the signals being tested.

Introducing full color displays

Just two years later, in 2002, a color display was introduced to the new 190 Series in the 199C. Now, the information for each channel was displayed in its own color unique color, leading to less confusion and fewer mistakes.

20 years from ScopeMeter’s beginnings: From two channels to four

All previous models, from the original 90 Series through the 190 Series, offered two input channels. Now, in the 20th year of the product line, four-channel units have been introduced in the 190-204, and all four inputs are fully isolated from one another. With Scope Record memory features, and an up-to-date USB interface, the 190 Series II continues the ScopeMeter tradition of continuous improvement.

But, perhaps the most significant specification advance is in safety. With the addition of a new family of test leads, these new products now join many other Fluke tools in meeting 1000v Category III and 600v Category IV working voltage conditions.

Twenty years…and there’s more to come!

Watch a video about the making of the ScopeMeter 190 Series II test tools »

Read “Improving on a legend: The story behind the new 190 Series II ScopeMeter” »

Find out more about the newest ScopeMeter test tools »