Drawing Number: 21113
Revision: A
OPERATION MANUAL FOR
ICP
®
HIGH PRESSURE SENSORS
Series 108 & 109
4
3.7
CIRCUIT CONNECTIONS
The figures below show two typical circuit
connections normally used to connect the 108 & 109
Series to power units.
The first figure is the connection scheme used for
most applications. In this set up, the signal is AC-
coupled from the bias voltage meaning the voltage at
the "scope" terminal will be at a zero volt bias level.
Normal Connection AC-Coupled Output
In this case, the system discharge time constant will
be determined by the input resistance and capacitance
of the power unit. Most PCB power units have
approximately a 10 second discharge time constant.
Alternate Connection to take Advantage of Sensor
Discharge TC
The second figure illustrates an optional connection
scheme which can be used during calibration to take
full advantage of the sensor’s discharge time constant.
With this arrangement, the readout is direct-coupled
to the sensor and the output signal will be added to
the DC bias voltage (11 VDC nominal).
The discharge time constant will then 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)
Typical Connection
The figure above shows the 108 & 109 Series
connected to a PCB Model 484B06 power unit. The
484B06 is a power unit that can be AC or DC-
coupled.
In the DC-couple mode, a level-shifting circuit
removes the bias level and provides a zero adjust
feature at the front panel. The system’s discharge
time constant is determined by the sensor in this
mode.
An AC-coupled mode is provided for normal AC-
coupled operation.
4.0
CALIBRATION
PCB 108 & 109 Series sensors are supplied with a
calibration
certification
from
the
factory.
Recalibration services are provided at the factory for
a nominal fee.
Static calibration methods may be employed using the
set-up shown in the Alternate Connection figure or by
use of the Model 484B06 Power Unit as shown in the
figure above – use the 484B06 in DC mode.
Following thermal stabilization of the sensor, use a
high pressure pump with dial reference sensor or a
dead weight tester to apply pressure in desired
increments to full scale. Release pressure after taking
the reading and before proceeding to the next higher
pressure level.
With a 2000 second discharge time constant, 1% of
the signal will be lost in 20 seconds, so it is
imperative that the pressure setting and recording of
output be accomplished quickly.
A calibration graph can be plotted using output
voltage vs. input pressure to determine sensitivity and
linearity.
108 & 109
SERIES
002 SERIES
ICP
®
POWER SUPPLY
READOUT
108 & 109
SERIES
ICP
®
POWER SUPPLY
002 SERIES
READOUT
ICP
®
POWER SUPPLY
SERIES 002
READOUT
108 & 109
SERIES