ME 4232 Fluid Power Controls Lab Lecture 8 03.09.2012 Dominic Triana
New Test Benches
Systems Overview
Potentiometer (pot)
Our Potentiometer Sensors
Hall-Effect Slope Sensor
The Hall Voltage is a function of the direction and magnitude of the magnetic field and electric current.
Load Cell
π
π‘ π
π πππ’π‘ = πππ( β ) π
π + π
π‘ π
π + π
π‘
Linear Variable Differential Transformer (LVDT)
πππ’π‘ πππ
=
πππ’π‘ πππ
Cool Animation
Systems Overview
Signal Conditioner β’ For LVDT, ratiometric comparison and conversion to DC voltage β’ DC voltage amplification (Gain)
β’ Low pass filter β’ Offset correction factor
β’ For servo valves, current driver
Voltage Amplifier
Filters
Current Driver
Systems Overview
A/D & D/A Converters
Nyquist Sampling Theorem βIf a function x(t) contains no frequencies higher than B hertz, it is completely determined by giving its ordinates at a series of points spaced 1/(2B) seconds apart.β
Lab Report Suggestions β’ Think about what you are testing and why. β’ When you make changes to the system what do you expect to happen? β’ Read about the components before lab. β’ What relationships are you testing or demonstrating? β’ What are the governing equations? β’ Think about what will produce useful measurements.
β’ Write for reproducibility. β’ Use correct circuit diagrams. β’ Label talking points on diagrams (needle valve A). β’ Do not use the words: very, much, extremely, etc. β’ Limit the use of βthatβ. β’ Take out fluff. β’ Reduce general statements. β’ PROOF READ!!! β’ Try reading out loud to yourself.
Questions about Systems Review???
Have a nice SAFE Spring Break!
