Operation – Parr Instrument 6755 User Manual

Page 11

Operation

6755

w w w . p a r r i n s t . c o m

Note:

Changes to the program are made by use

of the menu structure. Any of these items can

be individually entered at any time to revise the

operating program.

Default Settings
The 6772 Calorimetric Thermometer is prepro-
grammed with default settings for use with the 1341
Plain Jacket Calorimeter. On the operating controls
page of the 6772 Thermometer is the Method of Oper-
ation key. This key toggles the thermometer between
solution and combustion calorimetry. Make sure that
the calorimeter is set to solution calorimetry. This
will force the calorimeter to restart and bring up the
appropriate set of menus and eliminate all of the keys
dedicated to combustion calorimetry.

The default values of the 6772 are designed to oper-
ate with the 1341 Plain Jacket calorimeter. Therefore,
the following parameters must be changed in the
Calorimetry Parameters menu found in the Diagnos-
tics Menu.

Correction (K) Parameters:

0.5

0.00080

1.0

0.0

Blackout (B) Parameters:

Misﬁ re Blackout (B2)

Derivative Blackout (B3)

0.5

Dynamic Blackout (B4)

Equilibrium Blackout (B5)

Dynamic Derivative Blackout (B6)

0.02

Dynamic Time Blackout (B7)

Note:

To perform an endothermic run, set the

Tolerance Parameter (L2) to -1.

See Chapter 14: Default Settings for a listing of the
factory default settings. A more in-depth explanation
of these parameters is found on the corresponding
parameter group help pages. These default settings
remain in effect until changed by the user. Should
the user ever wish to return to the factory default set-
tings, go to the Program Info and Control Menu, User/
Factory Settings, touch Reload Factory Default Set-
tings and YES. Non-volatile memory is provided to
retain any and all operator initiated program changes;
even if power is interrupted or the unit is turned off.
If the unit experiences an intentional or unintentional

“Cold Restart”, the controller will return to the last
known settings.

The default parameters of the 6772 Calorimetric
Thermometer can be changed to guarantee that the
thermometer, when cold restarted, will always be in
the desired conﬁ guration before beginning a series
of tests. Users who wish to permanently revise their
default settings may do so using the following proce-
dure:

• Establish the operating parameters to be stored

as the user default settings.

• Go to the Program Info and Control Menu, User/

Factory Settings, User Setup ID, and enter the
desired User Setup ID.

• Select Save User Default Settings
• To re-load the user default setting, go to the

Program Info and Control Page, User/Factory
Settings, Re-load User Default Settings, and YES.

Performing an Analysis
Tests can be run in a strictly manual fashion or au-
tomatically where the thermometer sequences the
calorimeter through the pre and post periods. The
manual sequencing approach is useful for applica-
tions where raw data is logged and subsequently
analyzed, off-line. In the automatic mode, the ther-
mometer fully sequences the test and applies real
time corrections to the calorimeter temperature rise
in order to correct for all systemic heat leak effects.
In either case, the operator must determine the ap-
propriate temperature source for the jacket.

• Probe – This method uses a thermistor probe

attached to the jacket wall to measure the actual
temperature of the surroundings (at the chosen
point) and the heat leak corrections are based
upon the actual differences between the bucket
and this external jacket temperature.

• Calculated – During the initial equilibrium period

this method analyzes the actual heat leak rate
and calculates the apparent temperature of the
surroundings which would generate this rate and
applies this calculated jacket temperature for the
determination.

• Fixed – In this method the operator determines

what his jacket temperature will be and enters it
into the thermometer. All heat leak corrections are
then based upon this ﬁ xed jacket temperature.

For most applications the calculated method is rec-
ommended.