Drawing Number: 21114
Revision: NR
OPERATION MANUAL FOR
ICP
HIGH PRESSURE SENSOR
Series 108B
4
Model 108B
Readout Device
Model 482A
Model 012A
Cable
Type 002A
Cable
Figure 5a: Normal Connection AC-Coupled
Output
108A
002A
DC DVM
Model 070A01
"T" Adaptor
480B
Figure 5b: Alternate Connection to take
Advantage of Sensor Discharge TC
Figure 5 (a) is the most often used connection scheme
for most applications. In this set-up, the signal is AC-
coupled from the bias voltage by a 10
F capacitor
located in the power unit.
The voltage at the "scope" terminal will be at a " 0"
volt bias level.
In this case, the system discharge time constant will
be determined by the value of the input resistance (R)
of the readout device and the 10
F capacitor (C) in
accordance with the following relationship:
TC (seconds) = R (ohms) C (farads)
Figure 5 (b) illustrates an optional connection scheme
which can be used during calibration to take full
advantage of the sensor discharge time constant.
With this arrangement, the readout is direct-coupled
to the sensor and the output signal will be added to
the +11 volt (Nom) bias level.
The discharge time constant will now be determined
only by the sensor and should be in the order of 2000
seconds. This is sufficient for most types of static
calibration methods. (See calibration section 4.0.)
108B
Oscilloscope
DC DVM
Model 484B06
DC
Figure 6: Typical Connection
The above figure shows the 108B connected to the
Model 484B06 Power Unit. The 484B06 is a dual-
mode power unit, i.e. the output signal can be AC- or
DC-coupled from the sensor.
In the DC mode, a level-shifting circuit removes the
bias level and provides a zero adjust feature at the
front panel.
In the DC mode, the system discharge time constant
is determined by the sensor.
An AC-coupled mode is provided for normal AC-
coupled operation.
4.0
CALIBRATION
Static calibration methods may be employed using the
set-up shown in Figure 5 (b) or by use of the Model
484B06 Power Unit as shown in Figure 6. Use
484B06 in DC mode.
