WPI Biological Signals Amplifier, Instruction Manual, Page: 9 / 16

Biological Signals Amplifier
World Precision Instruments 5
NOTE : If the recorded output signals for the 10mmHg and 100mmHg settings
are not 100mVDC and 1VDC respectively, recalibrate the pressure sensor to the
HG1 module using the directions provided below.
6. Once the calibration of the sensor and amplifier have been verified, prepare to
attach the pressure sensor to the cannula or catheter. Purge all lines to remove
any bubbles in the perfusion fluid lines. When ready, adjust the positions of
the stopcocks on the sensor lines, and start recording changes in pressure by
turning the 4-way program switch on the front of the HG1 module to
MEAS .
7. If a second pressure recording is required, connect a second pressure sensor to
IN2 input socket of the HG2 amplifier module. Connect the OUT2 output socket
of the HG2 module to another analog input on the data recorder using a similar
output cable.
8. Check the baselines and calibration of the HG2 amplifier and it sensor using the
same procedures used on HG1.
Calibrating the Pressure Sensor to HG Module
1. Attach the pressure sensor and the recording system to the HG pressure module
as described in the previous section.
2. Turn the 4-way program switch on the front panel of HG amplifier to GND . Set
the BALANCE potentiometer to the middle position. Turn on the amplifier. A
signal of zero (0) volts is sent by the amplifier to the data recorder. If necessary,
set the baseline of the recording channel to zero (0) using the controls of the
data recording system.
3. Attach a certified manometer or blood pressure meter to the input port of the
pressure sensor. Set the pressure in the manometer or blood pressure meter to
zero(0) mm Hg
4. Turn the 4-way program switch to MEAS . If the baseline level on the recording
channel changes when this switch is moved from GND to MEAS , adjust the
LOW trimmer-potentiometer on the front panel of the module until the baseline
on the recording channel is set to zero (00). Remember that the manometer/BP
meter has to be set at 0mmHg throughout this step. Return the 4-way program
switch to
GND
before the next step.
5. Set the manometer/BP meter to
generate a pressure of 100mmHg.
Turn the 4-way program switch
to
MEAS . The baseline level on
the recording channel should
read 1VDC for the 100mmHg of
pressure. If the value is different,
adjust the
HIGH
potentiometer
until the voltage level on the
recording channel reads 1VDC.
Fig. 5—(Right) The HG pressure sensor.