Hermetically-Sealed 4-20mA LVDT Position Transmitters Operate in Hostile Environments

August 04, 2007 (PRLEAP.COM) Technology News
Macro Sensors, (www.macrosensors.com), specialists in the manufacture of LVDT-based linear position sensors and gaging probes, offers the HSI/R 750 Series of hermetically sealed, loop-powered 4-20mA position transmitters for a wide range of position monitoring and feedback applications.

Units are specifically designed for mechanical position measurement where a hard connection can be made to a test piece. The 4-20 mA current loop input/output of these rugged and robust devices enables easy field integration with PLCs, digital indicators, host computer-based data processing, and QC data collection systems. Units can be configured for either loop-powered, two-wire or externally powered three-wire sourcing output to address different I/O requirements in various applications.

Constructed entirely of TIG welded stainless steel and hermetically sealed against hostile environments to IEC standard IP-68, HSI/R 750 Series LVDTs can be installed in hostile environments while the loop wiring connects to remote indicators and/or controllers located in environments safe from hostile conditions. Units offer precise output with a maximum linearity error of 0.25% of full range output or better using a statistically best-fit straight line derived by the least squares method. For more precision measurement the HSI/R series is also available with +/-0.10% linearity.

Available in full ranges from 0.10 inches (2.5 mm) to 20 inches (500 mm), these ¾-inch (19mm) diameter LVDTs are available as either blind bore units (HSI 750 Series) terminated in a glass-sealed axial connector that prevents the core from passing completely through the coil assembly or in a through-bore design (HSIR 750 Series) with the connector mounted radially to facilitate easy access to either end of the LVDT’s core for better mechanical support and core guidance, as well as easier cleanout in dusty or gritty environments. The radial connector also allows a shorter installed length to the sensor compared to units of the same range with axial connectors. For position sensing that requires the opposite directional sense, HSI 750 transmitters are available with reversed output slope, which gives 20 mA when the core is first inserted, decreasing to 4 mA as the core moves inward.

HSI/R 750 Series transmitters offer the frictionless operation, high resolution, excellent repeatability, and low hysteresis associated with LVDT technology, along with the convenience and simplicity of a precalibrated 4-20 mA current loop operation. The built-in electronics operate over a wide range of loop supply voltages and resistances.

A mating connector plug is supplied with the HSI/R Series sensors. For more information about Macro Sensors’ lines of 4-20 mA LVDT transmitters, visit our web site at http://www.macrosensors.com/lvdt_macro_sensors/lvdt_products or contact us at sales@macrosensors.com

About Macro Sensors
Macro Sensors’ extensive line of LVDT-based linear and rotary sensors are used for linear position measurement and feedback in a variety of industrial applications including factory automation, motion control systems, metal fabricating, automotive assembly as well as power plants, gas/steam turbines. Incorporated in 1994, the Company offers more than 200 years of cumulative design and manufacturing experience by its key staff in serving its OEM and end-user international customer base. On June 1, 2005, Macro Sensors was acquired by AST, manufacturer of state-of-the-art Micro-Electro- Mechanical- Structures (MEMS) based pressure sensors, transducers, and transmitters. Common applications of AST sensor products are in industrial OEM, hydraulic systems, fuel cells, medical gases, HVAC/R, refrigeration, oil & gas exploration/production, and off-road vehicles. For more information on AST products and technology, visit the AST website at www.astsensors.com.