DESCRIPTION
The Ectron Model 451 is a unique advance in conditioners for
LVDT* and RVDT*
transducers. For the first time, the conditioner
can be calibrated to the transducer without using a costly
and time-consuming laboratory procedure. And autozero can be
commanded at any time. Plus, the Model 451’s display
indicates the analog output voltage and actual transducer displacement
in real time!
The Model 451 excites the transducer according to user set
parameters for voltage and frequency. A variable gain differential
amplifier receives the resulting signal which is then coupled
to a synchronous detector, user controlled four-step filter,
analog-to-digital converter, and micro-controller. Here, all
functions from arithmetic calculations, to front-panel data
and menu displays, to user interface operations are controlled.
In parallel, the displacement data is calculated and coupled
to the front panel for display. Finally, a digital-to-analog
converter and output analog stages produce the desired analog
output signal. The display indicates both the analog voltage
and the actual transducer displacement. Settings, maintained
in nonvolatile memory, are entered into the Model 451 using
the front panel controls.
OPERATING MODES
Example Mode
Mount the LVDT; then position the apparatus under
test to one position of its motion (usually one extreme)
and command the Model 451 to “capture” Point 1. Repeat with a
second position to “capture” Point 2. Then key
in the desired output voltages corresponding to the two points
and you’re through! For exact indication of displacement,
the sensitivity constant**
for the transducer must be entered.
Scale Mode
For the LVDT in use, key in two points of the expected
motion in units of displacement and the corresponding desired
output voltages, plus the sensitivity constant** of the transducer.
That’s it.
Gain Mode
Key in the desired conditioner gain. The analog output
voltage will equal the input voltage (from the transducer)
times this gain. This is the conventional operating mode of
existing LVDT conditioners. The Model 451 front panel will display
distance if the sensitivity constant** of the transducer
has been entered as well as the corresponding output voltage.
If desired, an autozero can be commanded at any time.
* LVDT—Linear
Variable Differential Transformer
* RVDT—Rotary Variable Differential Transformer
** The sensitivity constant of an LVDT, usually supplied
by the manufacturer, is a factor linking excitation voltage and
output voltage change to displacement. It is normally
expressed in mV output per volt of excitation voltage
per mil of displacement. For RVDT’s, the displacement is
normally in degrees. This constant can be accurately
measured using the Model 451.
400 SERIES ENCLOSURES
Ectron 400 Series enclosures provide connector interface for
power and signal input and output connections for 400 Series
products. Portable, bench mount, rack mount, and signal-conditioning
systems are available with capacities from 6 to 22 conditioners.
The following Ectron products are interchangeable in these
enclosures: the Models 352 and 428 conditioner amplifiers,
the Model 441A/AL frequency-to-voltage converter, and the Model
451 LVDT/RVDT signal conditioner. Thermocouple conditioning
can be added using the 200 Series T/C Mate.
Model E408-1D Channel Enclosure shown
with optional DIN rail mount
Model E408-6 Six Channel Portable Enclosure (front and rear views)
Model R408-14 Rack Mount Enclosure (front and rear view)
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