Malvern Visco 88, User Manual, Page: 36 / 74

Chapter 4 Other tasks
Page 4-2 MAN 0378
4
Adjusting the residual torque
Residual torque adjustment calculates the compensation needed to take account of
residual torque when at rest. Follow these guidelines:
„
Adjust the residual torque when the instrument is at rest before making the
first measurement after installation. After this we recommend repeating the
process at the start of each week.
„
Just before measuring any very low viscosity material, check whether it’s neces-
sary to repeat the adjustment.
To check whether adjustment is needed:
1.
Before any measuring system is attached, press the START button to start the
motor. (The SYSTEM switch can be in any position.)
2.
Press the FUNCTION button until the torque value, M (mNm) , appears on
the display.
3.
Run the motor for about 30 seconds. Turn the SPEED switch and read the
torque at speeds 1 to 4. If the torque value of any of the four lowest speeds is
greater than 0.01mNm, residual torque adjustment as described below is
needed.
4.
Press the
START
button to stop the motor.
To adjust residual torque:
1.
With no measuring system attached, press the START button with the
SPEED and SYSTEM switches in any position. If the motor is cold, let it
run for about 30 seconds.
2.
Press the START button to stop the motor.
3.
Press the FUNCTION button until Cal appears on the display.
4.
Hold the CAL button down until the motor starts.
The adjustment is performed automatically for all eight speeds, starting with the
highest.
Note
If the display shows
tRAP
(trap), turn the instrument off. Check that it is
vertical and that the AC adapter is connected, then power it on again.
If
tRAP
reappears a second time after this, contact Malvern Instruments.
i