Instruction Sheet
for the PASCO
Model CI-6532A
PRESSURE SENSOR - ABSOLUTE
012-06859B
10/98
$1.00
(0 TO 700 kPa)
polyurethane
tubing
quick release
connectors (4)
pressure port
connector
Introduction
The PASCO Model CI-6532A Pressure SensorAbsolute is designed to be used with a PASCO
Science Workshop
6532A includes the pressure sensor unit,
extension cable with 8-pin DIN connectors, quick
release connectors, polyurethane tubing, and a
syringe.
The pressure sensing element in the pressure
sensor unit has two pressure ports. One port is
connected to the atmosphere via the pressure port
connector at the front of the pressure sensor unit.
The other port is internal to the pressure sensing
element and is sealed with a reference vacuum.
The sensor element is designed to be used with
non-corrosive gases such as air, helium, nitrogen,
etc. Do not expose the sensor to liquids.
®
computer interface. The CI-
syringe
700 kPa MAX
DRY AIR ONLY
CONNECTOR:
PRESSURE PORT MATING
PASCO PART NO. 640-021
Equipment
cable with DIN
connectors
CI-6532A
PRESSURE
SENSOR
0-700 kPa
(ABSOLUTE)
Pressure Sensor
unit
INCLUDED
• Pressure Sensor (Absolute) unit
• quick-release connectors (4)
• polyurethane tubing (0.6m)
• plastic syringe (20cc, calibrated)
ADDITIONAL REQUIRED
• computer (PC or Macintosh)
• Science Workshop
• Science Workshop
higher
Extra parts are available as follows:
Item Part Number
plastic syringe 699-084
polyurethane tubing 640-023
quick-release connector 640-021
to computer
interface
®
computer interface
®
software version 2.2. or
© 1998 PASCO scientific
Pressure Sensor - Absolute (0 to 700 kPa) 012-06859B
T able 1
Pressure range comparison
kiloPascals inches of Hg mm of Hg Bar pounds/sq in atmospheres
700.00 207.25 5250.4 6.999 101.48 6.908
101.32 30.00 760.0 1.013 14.69 1.000
Range and Resolution
The range of the CI-6532A Absolute Pressure
Sensor is between 0 and 700 kiloPascals (or 0 to
6.9 atmospheres). Atmospheric pressure is
normally around 101.326 kiloPascals (kPa).
Pressure can be measured in many different units
(e.g., atmospheres, inches of mercury, millimeters
of mercury, kiloPascals, Bar, pounds per square
inch). Some equivalent values for pressure are:
1 atmosphere = 30.00 in of Hg (at 16ºC)
= 760 millimeters of Hg
= 101.326 kiloPascals (kPa)
= 1.013 Bar = 1013 milliBar
= 14.696 pounds per square inch (psi)
The top of the range of pressure expressed in these
equivalent units is as in Table 1.
The maximum short-term pressure that the sensor
can tolerate without permanent damage is about
1,000 kPa (150 psi). Please be careful to not apply
high pressure to the sensor.
The sensor box contains a precision operational
amplifier (op amp) that can drive a heavy
capacitive load, such as a six meter extender cable
(CI-6515). There is a resistor in parallel with the
transducer to compensate the sensor for
temperature induced variations. The sensor has a
negative temperature coefficient (resistance
decreases as temperature increases) and the resistor
has a positive temperature coefficient.
Operation
Setting up the Equipment
1. Connect the Pressure Sensor unit to analog
channel A, B, or C of the Science Workshop
computer interface box using the cable with
the DIN connectors (Figure 1). Alternatively,
the unit can be plugged directly into the
analog channel jack.
The output voltage from the sensor is +1.00 Volts
when the pressure is 100 kiloPascals (kPa), and the
output voltage is linear. Therefore, the output
voltage should be +7.00 Volts at the top of the
range (700 kPa). The resolution of the sensor is 0.5
kPa (when used with a PASCO computer
interface). This resolution translates into other
pressure units as follows:
Units Resolution
inches of Hg 0.148
mm of Hg 3.750
milliBar 5.088
pounds per square inch (psi) 0.072
atmospheres 0.004
(ABSOLUTE)
0-700 kPa
SENSOR
PRESSURE
CI-6532A
CONNECTOR:
PASCO PART NO. 640-021
PRESSURE PORT MATING
DRY AIR ONLY
700 kPa MAX
Figure 1
Connecting the amplifier box to the interface box
2
012-06859B Pressure Sensor - Absolute (0 to 700 kPa)
2. Connect the quick release connector to the
pressure port connector on the Pressure
Sensor unit.
The sensor is temperature compensated, therefore
changes in room temperature will not interfere with
the data.
Using the Syringe and Quick-Release Connectors
The Pressure Sensor is designed for experiments
such as those that study the gas laws or for the rate
of a chemical reaction by monitoring the increase
or decrease in pressure. For example, Boyle’s Law
is a classic physics (and chemistry) concept that
can be demonstrated using the sensor and the
syringe. See Figure 2.
quick release
connector
tip
5
10
connector is free to rotate even when the connector
is firmly attached to the port. See Figure 3.
Push the connec-
tor onto the
quick release
connector
pressure port
connector
Figure 3
Using the quick release connectors
pressure port.
Turn the connec-
tor clockwise until
it “clicks” (less
than 1/8 turn).
tubing
Mounting on an Experimental Apparatus
Use the 1/4-20 threaded connector located on the
bottom of the sensor box to secure the Pressure
Sensor to an experimental apparatus (Figure 4).
The alignment hole fits over an alignment pin
included on some PASCO apparatuses.
barb
tubing
Figure 2
Using the syringe
To connect the syringe to the sensor, cut a short
length of tubing (about one inch). Put the “barb”
end of one of the quick-release connectors into one
end of the short piece of tubing. Put the other end
of the tubing over the tip on the end of the syringe.
Note: You can lubricate the end of the barb to make
it easier to put into the short piece of tubing. Put a
very small amount of silicon oil or saliva onto the
barb and then wipe the barb with a cloth so there
is only a thin layer of lubricant on the barb.
Align the quick-release connector with the pressure
port connector of the sensor. Push the connector
onto the port, and then turn the connector
clockwise until it “clicks” into place (less than oneeighth of a turn). The barb of the quick-release
alignment hole
1/4-20 threaded
connector
Figure 4
Mounting connector and alignment hole
3
Pressure Sensor - Absolute (0 to 700 kPa) 012-06859B
Suggested Experiments
Boyle’s Law (pressure vs. volume)
Boyle’s Law is a classic experiment in physics
(and chemistry) that can be demonstrated using the
sensor and the syringe. Set the syringe to a position
such as 15 cc. Connect the syringe to the pressure
port connector on the sensor. Take data as you
change the volume, beginning with a volume that
is greater than your beginning volume (e.g., move
the syringe to 20 cc). Continue to take data as you
decrease the volume to 15 cc and below.
Gay-Lussac’s Law (pressure vs absolute
temperature)
Gay-Lussac’s Law states that if the volume
remains constant, the pressure of a container of gas
is directly proportional to its absolute temperature.
Set up a sealed container of air by attaching the
longer piece of plastic tubing to a stopper in a 125
mL Erlenmeyer flask. Connect the other end of the
tube to the pressure port connector. Place the flask
in water baths of different temperatures. Record
data on how the pressure changes with the
temperature changes.
Other
PASCO scientific also produces a Differential
Pressure Sensor (Model CI-6533) and a Barometer
(Model CI-6531). The Differential Pressure Sensor
is similar to the CI-6532A, except that both ports
of the transducer are open to the atmosphere. It is
designed for experiments where pressure differs
from one part of the apparatus to another, such as
in a Venturi tube or for a demonstration of
Bernoulli’s principle. The Barometer has a range
from 800 to 1100 milliBar (24 to 32 inches of
mercury). It is designed to be a reliable, accurate
pressure sensor for weather studies. It is
temperature compensated and has a voltage
regulator, so changes in temperature or changes in
the computer’s power supply will not interfere with
the data.
Pressure in Liquids
Put the end of the longer piece of tubing under
water. The pressure reading should increase by
0.0978 kPa (0.02896 in of mercury) per centimeter
of depth below the surface. You can also use a “J”
shaped tube to study how pressure relates to the
difference in heights of the liquid in the two parts
of the tube.
Studying Chemical Reactions by Monitoring
Pressure
Many chemical reactions produce gases that can
cause an increase in pressure in a sealed container.
The pressure change can be used to monitor the
rate of the reaction.
4
012-06859B Pressure Sensor - Absolute (0 to 700 kPa)
00
D
PR
Note: This instruction sheet was written assuming
that the user has a basic familiarity with
Science Workshop and has access to the User’s
Guide for Science Workshop. Users can gain
basic skills by working through the tutorial within
Science Workshop. Another useful resource is the
Quick Reference Card for Science Workshop.
DIN Connector Specifications
1: analog output (+), -10 to +10 V
2: analog output (-), signal ground
3: (no connection)
4: + 5 V DC power
5: power ground
6: +12 VDC power
7: -12 VDC power
8: (no connection)
6
1
4
7
8
3
5
2
Limited Warranty
PASCO scientific warrants the product to be free
from defects in materials and workmanship for a
period of one year from the date of shipment to the
customer. PASCO will repair or replace, at its
option, any part of the product which is deemed to
be defective in material or workmanship. The
warranty does not cover damage to the product
caused by abuse or improper use. Determination of
whether a product failure is the result of a
manufacturing defect or improper use by the
customer shall be made solely by PASCO
PASCO PART NO. 640-021
ESSURE PORT MATING
CONNECTOR:
RY AIR ONLY
kPa MAX
scientific. Responsibility for the return of
equipment for warranty repair belongs to the
customer. Equipment must be properly packed to
prevent damage and shipped postage or freight
prepaid. (Damage caused by improper packing of
the equipment for return shipment will not be
covered by the warranty.) Shipping costs for
returning the equipment after repair will be paid by
PASCO scientific.
Address: PASCO scientific
10101 Foothills Blvd.
Roseville, CA 95747-7100
Phone: (916) 786-3800
FAX: (916) 786-8905
email: techsupp@pasco.com
web: www.pasco.com
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Pressure Sensor - Absolute (0 to 700 kPa) 012-06859B
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