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Brookfield Engineering Labs., Inc. Page 38 M/02-212
• measuring system to be used in the measurement
• Number of steps
• start and end value of each step
• Number of measurement points for each step
• Duration of each step
preset value as a function of time:
D[1/s]=f(t)
0
20
40
60
80
100
0 60 120 180
t[s]
D[1/s]
As an example, we would like to consider a standard measurement.
1. Step: shear rate increases within 60 sec from 10.00 to 100.00 s
-1
.
2. Step: shear rate remains at the level of 100.00 s
-1
for 60 sec.
3. Step: shear rate decreases again within 60 sec from 100.00 to 10.00 s
-1
.
This measurement consists of 3 steps.
This example might be used to consider program input.
However, besides the shear rate D [s
-1
] = f(t), preset value can also be defined as:
Speed n[rpm]=f(t)
Torque M[‰]=f(t)
Shear stress Tau[Pa]=f(t)
Slopes and plain parts of the preset values are linear, measurement point is also defined linear, i.e.
there is no possibility to define logarithmic measurements. For logarithmic measurement you need
RHEO program package.
Preset value substeps in a defined step according to the following equation:
∆ Preset Value = End Value - Start Value/(Number of Measuring points - 1)
where ∆ Preset Value is the difference between preset value of measurement point n and
measurement point n+1.
The first preset value (=the first measurement point) is always the start value of the slope, the last
measurement point is determined by the end value. As for our example, in order to reach the values D=
10, 20, 30, ... , 100 [s
-1
] we need ∆ Preset Value of 10 [s
-1
]. So we need 10 measurement points.
Sample: 100-10/(10-1)=10.
Number of Measurement Points = (End Value - Start Value) / ∆Preset Value)+1
(for slopes only)
Let’s return back to the example.
After selection of the menue point “Edit Program” you will be requested to select a program from the list
of all programs available, which you want to generate or to edit.