Issued / Herausgegeben / Publicado / Pubblicato 09/1998
Instruction Leaflet
Bedienungsanleitung
Manual de instrucciones
Foglio d'instruzioni
Card function
The basic function of the card is to energise the transducer (LVDT, half
bridge) with an a.c. waveform take the output of the transducer and
convert it to a d.c. output voltage proportional to displacement, strain,
load etc. It should be powered from a stable twin rail d.c. supply at
±15V or ±12V.
CAH card block diagram
Figure 1
Transducer A
Transducer B
Each demodulator includes coarse
and fine gain and zero adjustments
The (A±B)/2 facility offers four outputs based on the two transducer
outputs (A and B). These are A + B, A - B, (A - B)/2 and these can be
used for measuring diameters etc. where two transducers are
involved. The current drivers are wired up separately and so can be
used with any of the d.c. outputs.In order to exploit the transducer to
the full, a number of facilities are provided. Span is adjustable in 9
coarse ranges and with a fine span control to allow the use of
transducers with sensitivities in the range 0.5mV/V to 750mV/V for a
full scale output of 5V d.c. Coarse and fine zero controls are provided
to enable the transducer to be zeroed anywhere in its stroke.
Two operating frequencies are provided, 5kHz and 10kHz, and the
output filter cut off frequency can be set to 500Hz or 1kHz to allow for
the best response time/output ripple trade off. The standard card is
provided with an input transformer and a pair of resistors to be used
when half bridge transducers are in use. These two resistors are
precision low drift types to reduce drift.
2 Channel LVDT Signal Conditioning Carrier
2-Kanal-, linear variabler Differentialtransformator-,
Eurokarten Ausführung, Oszillator/Demodulator (CAH)
T
arjeta amplificadora de portadora (CAH) para
acondicionamiento de señal LVDT, de 2 canales
Scheda amplificatore a onda portante (CAH) di
RS Stock No.
646-583
Oscillator
Frequency
hybrid
select
Demodulator
hybrid
Second
Demodulator
(if included)
adattamento del segnale per LVDT a 2 canali
To all
sections
(A±B)/2
circuit
(if included)
A + B A - B A + B A - B
2
2
Connections
Function
Power supply
+15V d.c.
0V
-15V d.c.
Transducer drive
Oscillator output (LVDT red)
Oscillator 0V return (LVDT blue)
Oscillator/2 for use with 1/2 - bridges
Synch (to synchronise cards)
Transducer screens
Channel A demodulator
Input (LVDT white)
Input return (LVDT green)
d.c. output
Channel B demodulator
Input (LVDT white)
Input return (LVDT green)
d.c. output
Amplifer (CAH) Card
Two current
drivers
d.c. output
channel A
d.c. output
channel B
Two current
Voltage input to
drivers
current drivers
from any input
Output currents
DIN 41612 pins
V7779
Power
supply
32a & c
30a & c
28a & c
22a & c
20a & c
18a & c
21a
24a & c
16a & c
14a & c
26a & c
19a
17a
23a