In a linear distribution the following applies:

Starting value = first measuring point End value = last measuring point

for each measuring point there is a change of the default size of:

delta = (end value – start value)/(#MP-1)

=> #MP = 1+( (end value – start value)/delta)

Example: You want to reach a sheer velocity ramp of 10 1/s to 100 1/s and the measuring points should be on even values 10, 20, 30, 40….100 1/s.

delta = 10 1/s Start value= 10 1/s End value= 100 1/s

#MP = 1+(100-10)/10= 10 You must thus choose #MP=10.

In a logarithmic distribution the following applies:

Start value = first measuring point End value = last measuring point

for each measuring point there is a change to the default size: delta = 10^((log(end value) - log(start value))/(#MP-1))

Warning: Rheometer with older firmware (version < 3.0) does not support the logarithmic measuring point distribution!!!

Related topics:

∙Block Overview

∙Temperature Regulation

Measuring Block for Rotation Stairs

In this measuring block a rotation step may be pre-defined in addition to the Temperature Regulation (7).

Figure 1: Rotation steps configuration for each table

Under (1) the test type can be chosen, CSS (shear stress specification) or CSR (shear rate specification). Depending on the type chosen you have the choice of different specification parameter available under "Parameter" (4).

In the section "Target value distribution" the time is specified for how long (3) a step is to be run and in what form the steps are to be specified, as a table as in (figure 1), or as an automatically calculated intermediate step of a start and end value (figure 2), linear or logarithmic.

Table Specification (Figure 1)

If under (2) the selection is set to "Table" then in the section "Table" a random amount of values may be added (10). For this purpose enter the values successively in the input field

(6) and click on the button "Add" (8).

Entries selected in (10) can be removed via the "Delete" button (9).

If a checkmark is set on (5), then the end value, if available, of the previous block is also transferred into the table.

Distribution between start & end value (figure 2)

In this case a stair is automatically calculated between the start value (32) and the end value (33), editable in the section "Start + End Value", with a specific number of steps (31), logarithmic or linear.

Figure 2: Rotation steps configuration via start & end value

Balance (11)

In the “Balance” section it can be specified as of what idle condition (maximum gradient (12)) the block measurement is to be started. Every dt (13) seconds a value is determined, the gradient is determined and it is checked if this one is smaller than the chosen one (12)? If yes then wait for the specified waiting period (14) before the actual block test will begin. However, only the maximum holding period (15) is checked, thereafter the execution is started no matter what.

Related topics:

∙Block Overview

∙Temperature Regulation

Export Storage Block

The storage block allows the filing in text format (.txt) or as an excel file (.xls) of the data collected to date (Excel is not yet supported). The file name can be specified, generated automatically or entered by the user during execution.

Figure 1: Storage block configuration dialog

(1)Selection field for the desired export format (txt, xls…)

(2)Separator for the data in a text file

(3)If chosen, the use is asked during execution to choose a target file.

(4)Default target file, via the button on the right, a target file may be searched

(5)If chosen, then an already existing file is overwritten else a “0” is added for the time being to the file name until an existing file is no longer found for it.

(6)If chosen, only the pure performance data are stored, else the program and block information are filed additionally.

If the checkmark under (3) is chosen then a dialog opens for the period (figure 2). In this dialog box the user may choose the file name to be used to export the data. For this purpose the window must be closed by clicking on “OK”, else the data is not saved.

Figure 2: Storage target – input request

Related topics:

∙Block Overview

Analysis Basics

This block allows to calculate some basic analysis methods to measuring data classified by physical parameters and source blocks.

Possible Calculations:

∙simple yield point calculation and per physical parameter 

∙Min (minimum value)

∙Max (maximum value)

∙AVG (average)

∙Eta(viscosity) on maximum point

∙Eta(viscosity) on minimum point

Configuration dialog

Image 1 : configuration dialog

(1)Basic analysis tabs, to change between main(basic analysis) settings and configuration of simple yield point analysis

(2)Source block selection field. Defines which data should be used.

(3)Selection whether or not for each block separate the analysis will be applied.

(4)Configuration table where you can select for each available physical parameter which calculation should be done. In this example the maximum, minimum and average for shear rate will be calculated and for shear stress the viscosity on minimum and maximum point.

(5)With the button you can clear all checkboxes in configuration table

The configuration of simple yield point analysis is equivalent to configuration part (11) of result window.

There are four properties for:

∙Enabled

should be the calculation applied?

∙Blocks(read-only)

display block numbers of selected blocks(selected on General tab)

∙Measuring point number

number of using measuring points if available

∙Start-Offset

measuring points are taken not until shear stress value is greater than start offset

Analyseergebnisse

Image 2 : basic analysis result

In this "Analysis Result" tab(Image 2) the results of basic analysis will be displayed in table format(21) . There will be only parameter rows displayed for that an calculation was selected in configuration table of (Image 1)(4).

Determination of yield stress (yield point)

The yield stress is the maximum shear stress before the onset of shear. The yield stress is calculated by linear regression of the first n measurement points with D[1/s]>x and subsequent calculation of the intercept of the axis of Tau[Pa] for D[1/s] = 0.

The values of x and n can be configured under (11).

n... Number of used measuring point

x... Maximal shear rate, only values >= x will be used

Image 3 : configuration & result of simple yield point calculation

On the tab "simple yield point" (Image 3) is under (11) the configuration again and under (12) the matching result displayed.

Related topics:

∙Block Overview

Thixotropy

Thixotropy – Area Calculation

The thixotropy area is the area between two data rows listed as Tau[Pa] = f (D[1/s]), whereby the data rows are divided into increasing and decreasing ramps. The calculation of the thixotropy area is completed as an integral of Tau[Pa]=f(D[1/s]) of all steps between the increasing and decreasing ramp.

(1)Here customized diagram and table settings may be made.

(2)Block selection field to choose the increasing and decreasing block

(3)short description of the chosen, increasing block

(4)short description of the chosen, decreasing block

(5)the two blocks can be swapped via the click of a button

(6)here it can be chosen which parameter is accepted as the x-value.

(7)with this checkmark it is specified if a suitable window is opened and if changes should be possible at run time.

Related topics:

∙Block Overview

∙Temperature Regulation

Event Block

Events are used to generate stop criteria of one or several following blocks of a measuring program. In a measurement it may for example be desirable to stop the process once the measured temperature is outside of a specified range. The following chapter explains a few examples on how stop criteria are generated. The stop criteria are specified in the event block.

Events consist of at least 4 parameters :

1. input size / parameter

e.g.: n[rpm], D[1/s], Tau[Pa], Eta[Pas], T[°C], M[%.], event counter

2.mathematical comparison operator

>(larger), < (smaller), != (uneven),= (equal), >= (larger or equal), < = (smaller or equal)

3.numerical comparison value 0.0 … 99999.9999

4.reaction if comparison applies

Cancel block

Cancel program

Reduce event counter (-1)

Increase event counter (+1)

Jump further to (to one of the following blocks)

Notification (open information window)

None

Reset event counter (=0)