Save time and money with field calibrators

 By Wayne Labs, Contributing Editor

ccurate instrumentation ensures accurate measurements that keep processes under control, prevent waste, and may protect human life as well. Field calibrators—also known as handheld calibrators—let engineers and technicians apply secondary calibration standards to devices and instrumentation without having to lug around heavy equipment. Today’s field calibrators work hand-in-hand with software, logging essential data when technicians use them on site. The software receives the original device data from the calibrator and provides it to the handheld calibrator when it’s time for the technician to make additional site visits.

Measuring and Calibrating Current Loops
Electrical engineer John Gale is responsible for the development, design, programming and engineering of industrial control, data acquisition, and continuous emissions monitoring systems for ACS, Inc. (www.acs-acs.com, Bellingham, Wash.), a company that designs and manufactures incineration and scrubber systems. Some of ACS’ systems have 24 current-loop inputs and 12 current-loop outputs that must be calibrated at commissioning and during routine maintenance and calibration intervals. To verify the accuracy of the equipment under calibration, Gale typically had to go through each loop several times.

ADVERTISEMENT GOES BOTH WAYS   Fluke's 789 Process Meter is both a digitial multimeter and a loop calibrator. It has a 24-V loop supply reducing the need for taking a separate power supply when doing offline transmitter testing.

Using Fluke’s (www.fluke.com, Everett, Wash.) ProcessMeter (Figure 1) which combines the functions of a traditional multimeter with a current loop calibrator, Gale reduced the time needed to calibrate the systems. In addition, on site visits he was able to eliminate one piece of equipment as well as extra batteries and test leads. With more than 30-years experience in the electronic/electrical industry, Gale has used several manufacturers’ meters and finds the ProcessMeter to be rugged, accurate, reliable, and with its large display, easy to read.

Smart Manometer Calibrator
BC Group International (www.bcgroupintl.com, St. Louis) is a leading provider of test and measurement equipment for the worldwide technical services marketplace. It is a one-stop-shop, offering sales of test equipment and tools, plus calibration and repair services for most types of test equipment. Over the last five years, BC Group has sold several hundred Meriam (www.meriam.com, Cleveland) Smart Manometer calibrators to a wide variety of instrumentation and control customers in a variety of industries including refining, chemicals, manufacturing, pharmaceuticals, food, and medical.

According to Mike Clotfelter, BC Group vice president, Business Development, what makes the Smart Manometer calibrator desirable is the display that provides engineering units in mm Hg, mBar, and psi—along with eight other engineering units. The accuracy specification is 0.05% full scale, approximately 72 psi on the Model 350DN2000 (Figure 2).

ACCURACY FOR OEMs
Meriam's Smart Manometer calibrator can be used for applications where very high accuracy is needed for gauge pressure of 20, 200, and 2000 psi.

“Until BC Group found the Smart Manometer,” says Clotfelter, “we had to offer two different manometers to obtain the range, engineering units, and accuracy required for servicing our applications.” According to Clotfelter, customers find the device to be very reliable and report that it stays within published specs year-after-year without calibration.
The calibrator handles clean, dry, non-corrosive gases; measures differential pressures of 20, 200 and 2,000 in. wc; checks gauge pressures of 20, 200 and 2,000 psi; and works in temperatures from -4–122° F. Pressure connections are 1/8-in. NPT. The device also handles absolute and vacuum pressures, and is NIST certified.

Documenting Acquired Data
The Industrial Company (TIC, www.tic-inc.com), through nine regional operations, provides industrial construction services to a diverse client base across the U.S. Headquartered in Steamboat Springs, Colo., the company typically uses its own engineering and construction people for the commissioning and startup of control system instrumentation.

According to Jim Mitchem, technology manager, checking out the hundreds of newly-arrived instruments and calibrating them prior to installation is largely a manual job, and recording these activities is often a problem. If the documents become illegible or lost, or the data itself is not secure, the calibration has to be redone, resulting in lost time and significant cost overruns. In addition, extra personnel are often needed to collect, review, edit and organize turnover documentation to determine that the calibration has been done correctly, and that all documentation is complete and accurate before presentation to the owner. The extra work can lead to missed project milestones and delayed completion dates.