The MR-7 Series LVIT (Linear Variable Inductance Transducer) Position Sensors from Alliance Sensors Group has been designed as an alternative to magnetostrictive sensors and has more robust construction and a lower cost of ownership. The unit can be port mounted in industrial or moble hydraulic cylinders and pneumatic actuators. These MR-7 Series sensors are based on a proprietary contactless inductive sensing technology that employs a 7 mm diameter probe with a shorter stroke-to-length ratio than most other technologies, and uses a gun drilled hole in the cylinder rod for sensing the rod position rather than requiring a ring magnet assembly. An MR-7 has a 1.75 inch (44.5 mm) hex sensor head with a male o-ring port thread, so it can be mounted in the same SAE dash 8 or 18 mm 0-ring port as magnetostrictive sensors. Because they are contactless, MR-7 Series sensors do not wear out and have no signal deterioration over the life of the sensors, and because it uses an inductive coil, an MR-7 sensor can withstand much greater shock and vibrations than other technologies. One very useful element of the MR-7 sensors is ASG’s proprietary SenSet™ feature whereby a sensor’s analog output can be easily adjusted in the field after installation too match the range of motion of the cylinder rod. Technical datasheets and additional information can be found below.
Analog I/Os: 0 – 5 V or 0.5 – 4.5 V output with 8 – 30 V input, 35 mA max. 0 – 10 V output with 12 – 30 V input, 35 mA max. 4 – 20 mA (3-wire) output with 18 – 30 V input, 60 mA max. (75 C max.)
Measuring Ranges: 0-25 mm to 0-600 mm (1 to 24 inches) Full Scale (nominal)
Linearity Error: ±0.15% of Full Scale Output (FSO) typical, ±0.25% of FSO max.
Resolution: 0.025% of FSO
Update Rate: 300 Hz nominal
Operating Temperature: -20 to 85 C (-40 C to 105 C Extended Range)
Temperature Coefficient: ≤±0.015% of FS/deg C
Operating Pressure: 5000 psig (350 bar) max operating, 7500 psig (520 bar) proof
Vibration: 5-20 Hz 0.5 inch p-p; 20-2000 Hz 4.2 g p-p
Shock: 1000g, 11 msec
Terminations: IEC IP-67
Humidity : 95% RH, non-condensing