Meriam Process Technologies has been supplying measurement and calibration products and solutions for 100 years. For the last 25, it has featured handheld versions of its products. Now Meriam has taken the expertise gained from these two-plus decades of experience in small, lightweight instruments, and brought it to the development of its first installed industrial pressure transmitter.
The M3500 is a high-accuracy industrial pressure transmitter with a custom cast aluminum enclosure suitable for field use. It is designed for use with process control applications on the plant floor or field installations where 24/7/365 use is required. It is communications-enabled using the wired HART 5 platform.
"For 25 years, we've been measuring with handheld devices," says Dave Thomas, product manager for Meriam Process Technologies. "Now we're transferring the expertise developed on the handheld side to installed process transmitters."
One of the important benefits of the M3500 is its accuracy. Typical accuracy is ±0.025% full-scale with no temperature-related degradation from -20 ºC to +50 ºC (-4 ºF to +122 ºF). Other industrial pressure transmitters offer an accuracy of ±0.04% to ±0.1%. Furthermore, "Most transmitters pay an accuracy penalty with temperature changes," says Thomas. "Full temperature compensation is one of the features we've leveraged from our handheld devices."
The M3500 offers differential, gauge, compound and absolute pressure types in a variety of pressure ranges from 17 PSIA to 3000 PSIG. Outputs include a digital display, 4-20 mA (two-wire), HART and two open collector-to-ground switches. Four pushbuttons located beneath the name plate enable users to manually program and maintain the M3500 for pressure, flow or level applications. Users can also program the transmitter with a HART communicator, such as the Meriam MFC 4150. Hardware is included for 2-in. pipe or wall mounting.
In addition to its high-accuracy and temperature stability, the M3500 offers a combination of small size and light weight—other features brought over from Meriam's handheld product lines. It weighs less than 3 lb, about 1/3 less than competitive transmitters. Furthermore, while the instrument head is about the same size as competitive transmitters, the pressure measuring cell is much smaller, so the total volume is approximately one-third less. "Instead of being about 42 cubic inches, our pressure cell is 1.1 cubic inches, making the overall M3500 about 45% smaller in terms of volume than most industrial pressure transmitters," says Thomas.
The M3500 can be set up for pressure, flow or level modes. In pressure applications, it measures PSI, inches of water (ref. 20 °C, 60 °F and 4 °C), kg/cm2, MPa, kPa, Pa, mbar, bar, cm of water (ref. 20 °C and 4 °C), ft of water (ref. 20 °C, 60 °F and 4 °C), inches of mercury @ 0 °C, mm of mercury @ 0 °C, oz/sq in. and user-defined units. In flow applications it measures volume flow: m3, l (liters), yd3, ft3, in3, U.S. gal, Imperial gal, barrels and user-defined units. In mass flow, it measures lbs, tons, kg, short tons, long tons and user-defined units. Time unit options include seconds, minutes, hours or days.
For level applications, the M3500 supports direct head or bubbler type inferred measurements. Users select calculation models for linear tanks (vertical), non-linear tanks (horizontal cylinders or spheres). It measures level in the following units: height—yd, ft, in., m, cm and mm; volume—in3, U.S. gal, Imperial gal, barrels, m3, liters, yd3, ft3, percent and user-defined unit (linear scaling constant); Mass: lb, tons, kg, short tons, long tons, percent, user-defined unit (linear scaling constant).
The M3500 is priced from $1000 to $1400, depending on accessories, and will be ready for shipment the end of this month.