Appendix B
B–44 TA I
NSTRUMENTS
TGA 2950
and the constant reaction rate (negative resolu-
tion setting) modes of the Hi-Res
TM
ramp
segment. There is no limit to how many times
the setting can be changed during a method.
Increasing sensitivity setting tends to increase
experiment time.
Understanding
Sensitivity Setting
The TGA 2950 Hi-Res
TM
control algorithms
have been pretuned to respond correctly to most
transition situations with the default sensitivity
setting of 1.0. This means that in most cases it
will not be necessary to adjust sensitivity setting
at all. The key is knowing when and how to
make the adjustment.
It is easy to confuse resolution setting and
sensitivity setting since both values can affect
the resolution of the TGA scan. However, there
is a simple way to think of the difference
between the two parameters.
Resolution setting controls the temperature at
which the transition will occur (i.e., how far
from the theoretical isothermal decomposition
temperature) by selecting the reaction rate (%/
minute) at which heating rate is reduced. The
closer the reaction is to the isothermal
decomposition temperature the lower the
reaction rate and the longer the reaction will
take. You will find that you can use the resolu-
tion setting to literally move the measurement of
transitions on the temperature axis. (See Figure
B.13, page B-61.)
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