Application Notes

Application Notes for Linear Position Sensors and Supporting Electronics. Provided by Alliance Sensors Group H. G. Schaevitz LLC. Would you like to discuss an application? Call us today 856-727-0250

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LVDT signal conditioner S1A Series solves the susceptibility to beat frequency interference between channels.

GE Gas Turbine LVDTs with an ASG S1A LVDT Signal Conditioner

By: Ed Herceg Chief Technology Officer

The Alliance Sensors Group model S1A module is the most advanced single channel LVDT signal conditioner available today. It will operate practically any LVDT currently on the market, but occasionally users can be confused by unusual LVDT configurations,

ASG LVDT signal conditioner using its RS-485 communication port

Operating an ASG LVDT signal conditioner using its RS-485 communication port

ASG LVDT signal conditioners incorporate an RS-485 two-wire multi-drop serial communications interface for up to 16 devices. This port enables half-duplex serial communication by which a module can be set up and calibrated remotely and system data can be read or stored on a PC running a terminal program like Hyper Terminal with a 2-wire RS-485 converter for the computer's serial port or USB port connected to terminals J3-1 and J3-2 of the signal conditioner. The communication parameters are: 9600 bps, no parity, 8 data bits, and 1 stop bit (9600, NP, 8, 1), with echo on. Be sure that the RS-485 connection for Data A (D-) is connected to J3-2 and Data B (D+) is connected to J3-1.

ASG LVDT Signal Conditioning modules Graphic User Interface (GUI) Instructions

1. Connect a 2-wire RS-485 port converter to the computer on which this GUI is to run and connect the converter's output terminals to the RS-485 bus connections on the LVDT module(s), Data A (D-) connects to terminal J3-2 and Data B (D+) connects to terminal J3-1, but always follow the data polarity (D) indicated above, regardless of the letters used for the data lines.

Linear Position Sensor Calibration using SenSet® Field Programmability

Alliance Sensors' LVIT Linear Position Sensors offer SenSet^® Field Programmability. SenSet^® allows the installer to very simply and quickly exactly match the full scale electrical output of a sensor to the actual mechanical movement range of the device in which the sensor is installed

Hydraulic Cylinder Position Sensor Application Information

ME Series Linear Position Sensor Installed in a Hydraulic Cylinder

Linear Position Sensor Installed in Hydraulic Cylinder

Alliance Sensors Group offers in-cylinder position sensors to replace magnetostrictive technology at a lower installed and ownership costs. The LVIT ME series embedded sensor is placed in the same location as the other technologies as shown above. The sensor uses the gun drilled hole in the rod and piston assembly as the target. Typically a 10mm dia. hole is drilled but other sizes can be sensed. The unit is provided with a cable outlet for the electrical connections.

Bridge Expansion / Rail Buckling Application Note

Bridge expansion and contraction due to seasonal heating and cooling is a common problem found in civil engineering. To combat this problem, engineers put expansion joints in the bridge to absorb these changes. This problem is compounded with railway bridges, where the expansion of a mile long section of rail could be as much as 4 ft over a temperature change in some climates of 100 degrees F. This could lead to rail buckling, known in the industry as “sun kink”, as shown below, and the derailment of a train.

LV-45 Linear Position Sensors Used In Bridge Health Monitoring System

An ongoing challenge in the USA is that our transportation infrastructure is aging, as attested to by the increasing traffic and the resulting load limits being placed on bridges. In the present technological world, bridge monitoring does not have to rely on periodic human inspections, but could rely instead on electronically monitoring a bridge’s health, so it can be maintained and repaired well before any structural integrity problem could develop.

Recommendations for DC power supplies and USB-based data acquisition hardware for use with ASG's signal conditioners and DC-operated sensors

DC Power Supplies

There are two distinct types of DC power supplies that convert the AC power line voltage into
DC voltage to operate electronic devices. Linear supplies use a transformer, rectifier diodes, a
regulator, and filtering to produce relatively clean DC, but they are limited to a narrow range of
power input voltages and are usually physically large. Switching supplies offer a wider range
of power input voltages and are usually smaller in size, but often have switching frequency

How to Use the Failure Warning Output at J2-2 of an ASG S1A LVDT Signal Conditioner

The S1A LVDT signal conditioner module offers an open-collector failure warning output signal which is available at J2-2 on the blue terminal block connector. This output is a connection to the collector of an internal transistor switch, whose factory default mode of operation is Normally Open (NO). In NO mode a device connected between the +24 V DC supply and J2-2 will have no current flow when the module is operating without error, producing a logic High (+24 V) at J2-2, but if a failure occurs, current will flow producing a logic Low (0) at J2-2.

GE Position Sensors on Power Gen Turbines

How they work and how to use them with a third-party LVDT signal conditioner designed specifically for Power Gen Applications

LVDTs (Linear Variable Differential Transformers) are very commonly used as position sensors in power plants throughout the world. Working from AC voltages and frequencies not available from power lines, LVDTs require a signal conditioner to provide the necessary operating power. Alliance Sensors Group's model S1A module, designed specifically to be used in power gen applications, is considered by many power gen users be the most advanced and easy to use single channel LVDT signal conditioner on the market today. It can operate practically any inductive or LVDT-type position sensor currently in use.

Quick Start Guide Installation of MR-7 Series In-cylinder Position Sensors

Mechanical installation: MR-7 in-cylinder position sensors are designed to be inserted into an o-ring port machined into the rear endcap of the hydraulic cylinder. Standard MR-7s use an SAE J1926-1 -8 port with a 3/4-16 UNF thread. Metric threaded versions use an ISO 1649-1 port with a M18 x 1.5 thread. Both ports are Illustrated below. For either size port, the sensor's male thread comes with a Viton o-ring installed.

SAE J1926-1 -8 Port

Quick Start Guide ME-7 In-cylinder Position Sensor Installation

Mechanical installation: An ASG ME-7 in-cylinder position sensors is embedded into a 48 mm diameter

cavity in the rear endcap of a hydraulic cylinder. It may be inserted from the front of an unassembled

cylinder or from the rear of a cylinder with a two-piece endcap with a separate end cover.

What's So Good About LVIT Technology and What Is It All About, Anyway?

Alliance Sensors Group, a division of H.G. Schaevitz, LLC, has developed a linear position sensing technology called LVIT that offers an excellent price-to-performance ratio compared to other linear position sensing technologies such as LVDTs, linear potentiometers, and magnetostrictive devices. Furthermore, LVITs can offer the best stroke-to-length ratio of any contactless linear position sensor, because their overall length only increases by a relatively small percentage beyond their stroke.

Hot Swapping S1A LVDT Signal Conditioning Modules

Under the right conditions, an S1A module can be "hot swapped" with another module having the same internal DIP switch settings and loaded with values in certain EEPROM locations that match those in the original module. If S1As are connected in a multi-module array, this process will take the selected module off-line, but if done carefully, will allow the remaining modules in the array to operate normally.

To prepare the replacement module for a hot swap, the configuration data of the original module, which should have been obtained previously and saved for a possible hot swap, is needed. If this data is not available, connect to the RS-485 port of the original module with a PC and terminal program, and use the Config command to get it. Using that data, set the internal DIP switches and jumpers of the new module to match, then power it up and use its RS-485 port as noted above to load the values of ADC HI, ADC Lo, In Pot, Gain, and, if needed, FOP, FD, and LF using the Set command for each value.

Find out why the new LVIT technology is so important for linear position measuring

There has been a revolution in the position sensor market with the development of low cost, high precision, inductive LVIT Technology developed by H. G. Schaevitz LLC dba Alliance Sensors Group in Moorestown, NJ.

LVIT Technology (Linear Variable Inductive Transducer) has significant advantages over LVDTs and Potentiometers having an excellent stroke-to-length ratio and using contactless, inductive technology; giving you best of all worlds at a cost-effective price. The LRS-18 series are designed for dimension or position measuring applications in factory automation and in various industrial and commercial applications such as automotive testing, mil/aero test stands, robotic arms, and packaging equipment.

Snow Plow Applications for ASG’s LR-27, MHP-7, and ME-7 Series Linear Position Sensors

Most snow plows utilize hydraulic actuators to raise and lower the plow blade, change the blade’s left-to-right surface contact angle, and adjust the plow blade’s front-to-back tilt angle. Typically, these plow positioning functions are under the plow operator’s control. However, the operator’s productivity can be improved and plow maintenance reduced if plow position feedback is made available to the operator in the vehicle’s cab. A further benefit to plow fleet operators is that the position sensors’ output could be transmitted along with the GPS location of the plow vehicles to a remote site, where the plow operating parameters can be logged and evaluated for productivity and maintenance analysis. In addition, there can be electronic systems on board the plow vehicle that utilize various sensors to evaluate snow pack compaction and related factors to automatically control the most important plow position parameters.

ME-7 - What’s in it

An established but disruptive technology is now displacing older technologies being used for in-cylinder hydraulic actuator position feedback. LVIT Technology™ is an inductive technology which has been replacing both magnetostrictive sensors that use time-of-flight measurement technology and resistive potentiometers to offer a very rugged sensor that does not wear out.

Our Technical Support Staff: We have more than 150 years and three generations in the position sensor business and are expert application engineers at what we sell. We have real world experience and know how to solve your measurement challenges. Need help technical help with your measurement application? Call us today 856-727-0250.

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