Cannon Instrument CMRV-4500 - Manual (Page 90)

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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
TO delete the point click Yes . To keep the selected point(s) click No .
Cooling profile limitations
CMRV cooling capacity The CMRV cooling capacity changes proportionally with the temperature
at which the instrument is controlling. Greater cooling capacity is
achieved at warmer temperatures, and capacity decreases as temperature
decreases. This makes linear rates-of-cooling impossible in relatively
short time frames.
Correcting profiles If the rate-of-cooling for a profile exceeds the cooling capacity of the
instrument, one of three things must be done:
Lengthen the time between the two fixed temperature points
Decrease the temperature change between the two fixed times
Apply a combination of the two previous options.
When a profile data point with a specified tolerance is entered in the
Profile Designer, software calculations are automatically made to deter-
mine if the rate-of-cooling relative to the previously-entered point is
within the instrument’s capability. It is assumed that the instrument can
achieve the temperature specified by the previous point. If no tolerance is
specified for that point, then this assumption may or may not be war-
ranted. For this reason, it is possible to design a profile that the instru-
ment is incapable of achieving. The software will only flag those points
that are absolutely impossible to realize. This suggests that experience
and experimentation are needed to properly design profiles which can be
run successfully.
NOTE The ASTM D 3829 and ASTM D 4684 profiles supplied with the MRVW
software define non-toleranced points which are outside of the
instrument’s capability, but these are merely necessary stepping stones
which permit the instrument to attain proper temperature control at the
subsequent temperatures that are toleranced.
Profile Designer test parameters
The Profile Designer displays important test parameters for Yield Stress
and Viscosity testing. These values are editable from the Profile Editor.
For all ASTM profiles in the profile library, these values have been preset
in conformity with current ASTM specifications.