Cannon Instrument CMRV-4500 User Manual

Page 45

CANNON

Mini-Rotary Viscometer CMRV-4500 Instruction & Operation Manual

Version 1.1e—October, 2011 •

CANNON

Instrument Company

2139 High Tech Road • State College, PA • 16803 • USA

7. Remove the Plexiglas

cover and align the pulley-wheel with the cell

to be calibrated.

8. Place the thread from this cell over the pulley-wheel. Hook the

calibration weight specified by the Method to the end of the thread
(see photo).

9. From the

Calibrate

window, click the desired cell number for

calibration.

10. Press the blinking

Start Test

button on the CMRV controller.

11. Raise the locking pin quickly and smoothly. The weight will apply

torque to the rotor. The computer will record the time for three
complete revolutions.

12. Permit the wheel to make at least three complete revolutions (the

viscosity LED will go out). Then catch and remove the 150-gram
weight before the thread is completely unwound. Do not permit the
thread to completely unwind.

NOTE

After the rotor revolution time has been recorded, the program will
calculate the calibration constant for that cell.

13. At the conclusion of the test, the VISCPRO® software will display

the newly-calculated calibration constants.

NOTE

If the new constants vary from the previous cell constants by more than 4
percent, an error will be generated. It is generally advisable to recalibrate
the cell in this instance.

NOTE

To view previously-stored calibration constants, click Configure/MRV/
View Cell Constants.

14. Repeat the above calibration routine for the remaining cells.

Limiting calibration time

It is recommended that you perform the cell calibration immediately
following the one-hour sample soak time. Although

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viscosity

standards N105B and N400B have been dewaxed to a very low tempera-
ture, the standard should not be allowed to soak at -20°C for more than
two hours. The small amount of wax which may be in the oil could cause
an error in calibration.

NOTE

If any cell has a calibration constant more than 10 percent higher or
lower than the average for the other cells, the fault may be excessive
friction in the upper bearing, improper seating of the lower bearing, or a
damaged rotor tip. Examine the rotor for damage and, if necessary,
replace the rotor and recalibrate the cell.

Saving calibration data

15. At the conclusion of the calibration, review the displayed data in the

Calibrate Cell Constants

window. If the data is not acceptable,

recalibrate as necessary.