Tech Note 226 Detail

Calibration

Affected Products:

CI-6537 Force Sensor
CI-6746 Economy Force Sensor

Problem/Symptom:
How do I calibrate the Force Sensor?

PASCO Solution:
Connect the CI-6537 force sensor to an analog channel on your interface. Be sure to push firmly on the plug to insure a proper connection. Hang the force sensor from a rod stand so the weighing hook is pointing downward.

In ScienceWorkshop, set up the sensor as usual by clicking on the analog sensor plug icon, dragging it to the appropriate channel, and the selecting the force sensor from the analog sensor list.

Double click on the force sensor icon to open the calibration window for the force sensor.

In the calibration window, check that the sensitivity is set to Low (1x).

In the Calibration window you will see 3 rows labeled: High Value: Low Value: Cur(rent) Value:

The Current Value row shows you the actual voltage output from the sensor. Push the tare button on the force sensor. You should see the Current Value for voltage (second column) read very close to zero. The reading will fluctuate but it should read 0.000 +/-0.005 V. If the force sensor does not tare close to 0.000 V then something is probably wrong with your force sensor.

If the voltage is close to 0.000 V you can click on the Read Button for the High Value. Manually change the value in the Units box from 50.000 to 0.000.

Next, hang a mass of known weight from the force sensor. Look at the Current Value for Voltage. The CI-6537 should have an output close to 1.568 volts for every 1000g. Thus, of example, if you hung a 500 g mass, the Current Value for Voltage should read close to -0.784 V. Calculate the expected voltage for the mass you used. The voltage will be negative due to the orientation of the force sensor. There might be some fluctuation, but the voltage should read within +/- 0.005V from the calculated value for the mass you hung. If you now double the mass, you should see the Voltage increase proportionally. If this is not the case then something is probably wrong with your force sensor.

If your force sensor is working properly, click on the Read button for the Low Value. Enter the weight of the object, in Newtons, in the Units box for the Low Value. NOTE: Be sure to include a negative sign in front of the number.

Your force sensor should now be properly calibrated. Click on OK to accept the calibration. When using the force sensor, be sure to tare the force sensor often, as the zero calibration will drift slowly with time.

If after trying the above procedure, your force sensor is not working properly, you should contact your Customer Service Representative to arrange to have your force sensor repaired.

Creation Date: 01/1/2000
Last Modified: 02/18/2004
Mod Summary: