PASCO CI-6730A User Manual

Instruction Sheet
for the PASCO
Model CI-6730A

Close-up view of the propeller

012-08624A

Flow Rate Sensor

propeller

Flow Rate Sensor

propeller

digital plug for computer
interface

Introduction

The PASCO CI-6730A Flow Rate Sensor measures flow
rate in feet/sec (or meters/sec) and is designed for use with a
PASCO 500 or 750 computer interface. The CI-6730A
Flow Rate Sensor comes labeled with a metric/english
measurement scale and is expandable to seven feet.

The Flow Rate Sensor transforms the kinetic energy of
moving water into electric pulses that can be converted into
measurements and viewed in DataStudio software. The
Model CI-6730A Flow Rate Sensor differs from the
previous CI-6730 Flow Rate Sensor in that it uses a Hall
effect sensing element instead of a magnetic reed switch. A
Hall effect sensing element minimizes artifact pulses that
sometimes occur with a magnetic reed switch, allowing for
improved accuracy.

The Flow Rate Sensor uses a removable turboprop propeller
that rotates when only a small amount of water moves past
it. The turboprop is mounted on a low-friction brass shaft, is
protected inside a 2-inch diameter housing, and is designed
to shed debris. There is no direct mechanical linkage
between the turboprop and the sensing element that might
interfere with the free movement of the prop.

The propeller has two magnets. When the propeller
rotates, the Hall effect sensing element built into the
housing of the Flow Rate Sensor generates an electrical
impulse. The propeller makes 4.31 revolutions for each
linear foot of water that passes, so 8.62 pulses are
produced for each linear foot of water passing through
the housing. Thus, the rate at which the impulses are
generated is directly proportional to the flow rate.

The Flow Rate Sensor feeds the electrical pulses into
DataStudio through a digital port in the 500 or 750
computer interface. In DataStudio, the time between the
electric pulses is measured and converted to velocity
measurements (feet/second). Other units, such as
nautical miles per hour (knots), meters per second, or
miles per hour, may be defined by the user in
DataStudio’s Experiment Calculator.

Equipment included:

• Flow Rate Sensor

Additional Equipment Required:

• A PASCO ScienceWorkshop® computer interface
[500 (for outdoors) or 750 (for classroom)]

• Computer

Flow Rate Sensor 012-08624A

Flow Rate Sensor Operation

➤Note: The PASCO 500 computer interface is
recommended for outdoor studies of flow rate. Before
collecting data in the field, ensure that the 500 interface
contains four fresh AA batteries.

1. Connect the 500 interface to your computer with the
supplied cables. (Follow the connections instructions
provided with the 500 interface and/or installation
instructions in the DataStudio online help.)

2. On the back of the interface, use the On/Off button to

turn on the interface.

3. Plug the Flow Rate Sensor into one of the digital ports

of the computer interface.

ANALOG CHANNELS



ScienceWorkshop

®

s

n

A

C

500

E

S

R

S

P

T

G

O

O

L

Figure 1:

Inserting the Flow Rate Sensor’s digital plug
into a digital port on the computer interface

B

Interface

1

2

ON

=

GAIN

=

GAIN

1,10:ISOLATED

DIGITAL CHANNELS

1,10: REF TO GND

1: REF TO GND

Plug into a digital
channel port

=

GAIN

your collected data into a DataStudio display, press the
Connect button on the Setup toolbar.

10. To view a graph of a data run, drag a run icon from the
Data window to a Graph display.

➤Note: To express the velocity in terms of meters/
second, miles/hour, or knots, create the appropriate
calculation in the DataStudio’s Experiment Calculator.

Sensor Usage Tips

SAFETY TIPS: When using the Flow Rate Sensor

outdoors, follow standard water and outdoor safety
precautions. The Flow Rate Sensor is recommended for
use in streams and lakes (avoid turbulent waters or rivers).
Always inform students of potential hazardous conditions
in the area. Do not use the sensor in high winds, adverse
weather or avalanche conditions, near potential land or
mudslides, or when standing on unstable ground. Before
using the sensor, survey the area. When inserting the Flow
Rate Sensor into water, stand on stable ground or in
shallow water. Keep the Flow Rate Sensor away from
water that has lots of debris or potential obstacles. If the
propeller or sensor becomes lodged in a high velocity
current or near a drop off, do not attempt to remove the
sensor. In high risk situations, only allow a water patrol
officer or public safety official to remove the sensor.

4. Start DataStudio. From the Sensors list, drag and drop
the Flow Rate icon to the digital port icon that
corresponds to the digital port you are using on the
computer interface.

5. If the flow rate is expected to be less than 1 ft./s,
decrease the sample rate to 2 seconds per sample. (To
change the sample rate, double click the sensor icon.
In the dialog box, select the General tab and change the
sample rate. Click OK.)

6. On the Setup toolbar, click the Logging button and
follow the prompts. Disconnect the 500 interface for
remote data logging. (For more information on remote
data logging, see “Remote Data Logging” in the table of
contents of the DataStudio online help.)

7. At the field site: Insert the propeller of the Flow Rate
Sensor into the body of water to be measured.

8. To record data, press the LOG button on the interface.
To end data collection, press the LOG button again.
(Note: Do not turn off your interface or you will lose all
of the data you recorded.)

9. Reconnect the interface to your computer. To retrieve

• Always hold the pole vertically and keep the propeller

in the direction of the current flow, facing upstream.

• For higher water velocities (around >1 m/s), a sample

rate of 2 samples/sec is recommended.

• When taking a reading, keep the handle steady.

• If the flow rate reading suddenly falls to zero

midstream, check the propeller for debris. When sand
or other particles become lodged in the propeller, the
propeller stops turning and the reading drops to zero.

• Erratic readings may occur with turbulent water flow.

If measuring flow from a stream or creek, keep the
housing in a stable position, away from rocks and
turbulence. If measuring in low depths, you can rest
the housing on the stream bed for a more stable
reading.

• Do not connect the propeller housing to pipes or

other tubing.

• When not using the Flow Rate Sensor, store the

sensor in a dry environment to avoid corrosion. If
necessary, periodically lubricate the propeller with
silicone oil.

2