Ultra-Precise Spring-Loaded LVDT Linear Position Sensors Ensure Proper Operation of Pneumatic Cylinders

Pennsauken, NJ, November 23, 2015 (Newswire.com) - Macro Sensors offers the BBP Series of Air Extended, Spring-Loaded LVDT Position Sensors for these types of applications.  The position sensors features a probe that moves out and makes measurements only near the very end of the probe movement when it is almost fully extended and then retracts so the probe gets out of the way of damage.

These 3/8” inch diameter pencil type gaging probes measure the position of a target surface with an unusually high degree of accuracy. Because probe measurement is made only near the very end of the probe movement, such as when it is almost all the way extended, a short range LVDT can be used to get high resolution. In this configuration, a short range LVDT linear position sensor (0.050” to 0.125”) that measures a short distance can be used to get highest resolution as the full range of the cylinder stroke often does not have to be measured. 

Macro Sensors has found that many users do not want to measure the total range of the cylinder; they just need to get the probe out of the way of damage.  In these applications, a one or two-inch stroke cylinder can use a short range spring-loaded LVDT to measure a nominal plus or minus one millimeter at full probe extension before the probe retracts.  And because the LVDT does retract when not making measurement, the cylinder is retracted to get the ram and the gaging tip out of the way for manually loading parts, parts coming in from transfer lines, heavy parts getting banged and bounced in a foundry, etc.

 By combining the BBP Series Spring-Loaded Position Sensors with the LVC 4000 LVDT Signal Conditioner, Macro Sensors offers a fully calibrated and complete linear position gaging system ready for immediate operation.  To provide excitation and signal conditioning for these AC-operated LVDTs, complex electronics in the form a signal conditioner are needed that can generate the drive signal and read the output signals over some length of cable.  The LVC 4000 interfaces with the BBP Series to provide analog or digital RS-485 outputs that can be read on process control systems such DCS, PLC or others.

About the BBP Series of Spring Loaded LVDT Position Sensors

In addition to pneumatic cylinders, Macro Sensors BBP family of pencil-type gaging probes offers ultra-precise measurement of dimensions in a wide variety of other Q.C., SPC, and industrial metrology applications. Complete systems for “go/no/go” inspection of complex mechanical parts can be assembled using several gage heads mounted in suitable fixtures. 

Sensors utilize a linear ball bearing assembly precisely fitted to a hardened-and-ground, non-rotating probe shaft to minimize radial play and the effects of side loading. This results in the probes' exceptional repeatability of 0.000006 inch (0.15 μm).

The other end of the shaft is internally threaded to accept an interchangeable tungsten carbide contact tip for wear resistance and reliability. During measurement cycles, the shaft is extended by low-pressure (10-30 psi), clean, dry air supply, with a regulated flow, through a barbed fitting on the end of the unit for 1/8 inch I.D. hose. With the release of pressure, an internal spring returns the probe to its normal position. The entire bearing, shaft, and LVDT assembly are enclosed in a 3/8 inch diameter stainless steel tubular housing.

Other notable features of these spring-loaded LVDTs include:

·         User-adjustable pretravel

·         Reduced susceptibility to temperature changes

·         Positive stops prevent mechanical damage to the probe from repeated overstroking

·         Rubber bellows covering the probe shaft prevent the entrance of contaminants into the bearing.

BBP units are available in three standard ranges: +0.040” (+1.0 mm), +0.100” (+2.5 mm) and +0.200” (+5.0mm).  Gaging probes are available in a 3/8” diameter plain housing or one that is partially threaded with industry standard 3/8-40 UNS thread.