PASCO CI-6746 ECONOMY FORCE SENSOR User Manual

Page 3

012-06906B

Economy Force Sensor

Calibrating the Economy Force Sensor

The Economy Force Sensor is designed to produce

approximately zero volts when it is “zeroed”. A

change in force of one newton causes a change in

output voltage of 160 millivolts (0.160 V);

therefore, the sensor does not need to be

calibrated. Instead, the voltage can be converted

directly into force. For example, after the sensor is

“zeroed”, an output voltage of 0.160 volts equals a

force of one newton, a voltage of 1.60 volts equals

a force of 10 newtons, and so on. In the same way,

a voltage of -1.60 volts equals a force of -10

newtons (in other words, a pull of 10 newtons).

However, you can calibrate the sensor to learn

about the process of calibration. All calibrations

assume that the sensor produces an output

voltage that is linear with respect to the input

signal. Calibration is done by setting up two

calibration situations (such as “no force” and a

known force), measuring the input signal in each

situation in comparison to a known standard,

and entering the readings.

General Calibration Procedure:

1. In your data acquisition software, open the

Force Sensor’s calibration dialog.

2. Place your Force Sensor in the lowest force

situation for which you are calibrating (such as,

no force).

3. Press the tare button to “zero” the Force Sensor.

4. In the calibration dialog, type the low value into

the LOW VALUE text box, and click the

READ button.

5. Apply a known force to the Force Sensor (for

example, hang a mass of known weight from

the detachable hook). This force should be

approximately that of the highest force you plan

to measure.

6. Type the value for the applied force in the

HIGH VALUE text box, and click the READ

button.

Suggested Experiments

Component of Force on an Inclined Plane

When a cart is at rest on an inclined plane, the

component of force acting on the cart that is

parallel to the plane is mgsin

, where mg is the

weight of the cart and

is the angle of the plane.

Use the sensor to measure the weight of a

Dynamics Cart. Mount the sensor at the high end

of the inclined Dynamics Track using an

Accessory Bracket (CI-6545), and connect it to a

Dynamics Cart on the track with a string. Measure

the angle of the track. Measure the tension in the

string, and compare this to the theoretical value

mgsin

Newton’s Second Law: Pushing and Pulling a

Cart

When an object is accelerated by a net force, the

acceleration is directly proportional to the net force

and inversely proportional to the object’s mass.

Mount the Force Sensor onto a Dynamics Cart.

Use a Motion Sensor to measure the velocity and

acceleration of the cart. Zero the Force Sensor.

Hold the hook on the front of the Force Sensor,

and move the cart gently but irregularly back and

forth in front of the Motion Sensor. Use the

computer program to compare the measured force

to the measured velocity and acceleration.

Motion Sensor

to computer interface

Dyanmics Cart

Dynamics Track

Force Sensor

Dynamics
Cart

to computer
interface

Force Sensor

Dynamics Track

mgcos

mgsin

Accessory
Bracket