the torque arm of the dynamometer to insure that there is no force being applied to the load cell (which would result in an inaccurate zero calibration). Remove the calibration access cover panel and set the calibration mode switch to the ZERO position. Also, be sure that the shunt resistor switch is set to the OFF position. At this time note that the RPM display of the unit should indicate “1111” and the POWER display should indicate “0000”. The TORQUE display indicates the TORQUE and should read near zero. If the torque indication is excessive (plus or minus), the POWER display will read “EEEE” – which indicates that the zero offset of the load cell is excessive and that the ZERO calibration cannot proceed (see calibration notes below). Otherwise, press and release the ENTER push-button switch to perform the zero calibration. At this point, the TORQUE display should indicate zero and the zero calibration procedure has been completed.
2.) Set the TORQUE SPAN calibration: Apply the CALIBRATION TORQUE (see calibration torque notes below) to the unit and set the calibration mode switch to the SPAN position. At this point the RPM display should indicate “2222”, the POWER display should indicate “0000”, and the TORQUE display should indicate a value approximately equal to the CALIBRATION TORQUE. If the deviation between the torque reading and the calibration torque is excessive, the POWER display will read “EEEE” – indicating that the TORQUE SPAN calibration cannot proceed (see calibration notes below). Otherwise, press and release the ENTER
3.) Resume normal operation: Set the calibration mode switch back to the OFF (center) position. This turns off calibration mode and restores the unit to normal operation. Be sure to return the shunt resistor switch to the OFF position (if you used it during the torque span calibration). Replace the calibration access cover panel. The unit has now been accurately calibrated.
Calibration Procedure Notes:
1.ZERO CALIBRATION cannot proceed. This problem occurs when the ZERO OFFSET is excessive – too large for the zero offset correction facility of the 2400S to correct. Check the following:
1.1Make sure that the load cell is properly connected to the 2400S horsepower computer. Inspect the cable for damage, especially at the load cell end and the connector end. Make sure the connector is securely fastened to the 2400S torque sensor connector.
1.2Make sure that the load has been completely removed from the load cell. “Rock” the drive shaft of the dynamometer CW and CCW slightly (applying a small
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