Sampling Trace

x Dialog box for Program Call Entry

In the field, specify a valid program name for your project, or open the Input Assistant with the Select button to select a valid program name. If the selected program requires input variables, then enter these in their usual form and of the declared type (for example, prg(invar:=17)).

6.5.5 'Extras' 'Edit Entry'

Depending on the element selected, you can use this command in the Task Configuration to open either the dialog box for setting the task attributes (see 'Insert' 'Task') or the dialog box for entering the program call (see 'Insert' 'Program Call').

If the cursor is located at the task entry, and there is no list of program calls appended to the task entry, then you open the dialog for setting the doubleclicking on the entry or by pressing <Enter>.

If the cursor is located on an entry for a program call, then you can also open the dialog box for editing the program entry by doubleclicking on the entry.

By clicking on the task or program name, or by pressing the <Space bar>, you can set an edit control box around the name. Then, you can change the designation directly in the task editor.

6.5.6 'Extras' 'Set Debug Task'

With this command a debugging task can be set in Online mode in the Task Configuration. The text [DEBUG] will appear after the set task.

The debugging capabilities apply, then, only to this task. In other words, the program only stops at a breakpoint if the program is gone through by the set task.

6.6 Sampling Trace

Sample tracing means that the progression of values for variables is traced over a certain time frame. These values are written in a ring buffer (trace buffer). If the memory is full, then the "oldest" values from the start of the memory will be overwritten. As a maximum, 20 variables can be traced at the same time. A maximum of 500 values can be traced per variable.

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Sampling Trace

Since the size of the trace buffer in the PLC has a fixed value, in the event of very many or very wide variables (DWORD), fewer than 500 values can be traced.

Example: if 10 WORD variables are traced and if the memory in the PLC is 5000 bytes long, then, for every variable, 250 values can be traced.

In order to be able to perform a trace, open the object for a Sampling Trace in the Resources register card in the Object Organizer. After this, you must enter the trace variables to be traced. (See 'Extras' 'Trace Configuration'.) After you have sent the configuration with 'Save Trace' to the PLC and have started the trace in the PLC ('Start Trace'), then the values of the variables will be traced. With 'Read Trace', the final traced values will be read out and displayed graphically as curves.

6.6.1 'Extras' 'Trace Configuration'

With this command you will be given the dialog box for entering the variables to be traced, as well as diverse trace parameters for the Sampling Trace. The dialog can also be opened by a double click in the grey area of the dialog Sampling Trace.

x Dialog Box for Trace Configuration

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The list of the Variables to be traced is initially empty. In order to append a variable the variable must be entered in the field under the list. Following this, you can use the Add button or the <Enter> to append the variable to the list. You can also use the Input Assistant.

A variable is deleted from the list when you select the variable and then press the Delete button.

A Boolean or analogue variable can be entered into the field Trigger Variable. The input assistance can also be used here. The trigger variable describes the termination condition of the trace. In Trigger Level you enter the level of an analogue trigger variable at which the trigger event occurs. When Trigger edge positive is selected the trigger event occurs after an ascending edge of the Boolean trigger variable or when an analogue variable has passed through the trigger level from below to above. Negative causes triggering after a descending edge or when an analogue variable went from above to below. Both causes triggering for both descending and ascending edges or by a positive or negative pass, whereas none does not initiate a triggering event at all. Trigger Position is used to set the percentage of the measured value which will be recorded before the trigger event occurs. If, for example, you enter 25 here then 25 % of the measured values are shown

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before the triggering event and 75% afterwards and then the trace is terminated. The field Sample Rate is used set the time period between two recordings in milliseconds. The default value "0" means one scanning procedure per cycle.

Select the mode for recalling the recorded values: With Single the Number of the defined samples are displayed one time. With Continuous the reading of the recording of the defined number of measured values is initiated anew each time. If, for example, you enter the number '35' the first display contains the first measured values 1 to 35 and the recording of the next 35 measured values (36-70) will then be automatically read, etc.. Manual selection is used to read the trace recordings specifically with 'Extras' 'Read trace'.

The recall mode functions independently of whether a trigger variable is set or not. If no trigger variable is set the trace buffer will be filled with the defined number of measured values and the buffer contents will be read and displayed on recall.

The button Save is used to store the trace configuration which has been created in a file. The standard window "File save as" is opened for this purpose.

Stored trace configurations can be retrieved using the button Load. The standard window "File open" is opened for this purpose.

Note:

Please note that Save and Load in the configuration dialog only relates to the configuration, not to the values of a trace recording (in contrast to the menu commands 'Extras' 'Save trace' and 'Extras' 'Load trace').

If the field Trigger Variable is empty, the trace recording will run endlessly and can be stopped by 'Extras' 'Stop Trace'.

6.6.2 'Extra' 'Start Trace'

Symbol:

With this command the trace configuration is transferred to the PLC and the trace sampling is started in the PLC.

6.6.3 'Extra' 'Read Trace'

Symbol:

With this command the present trace buffer is read from the PLC, and the values of the selected variables are displayed.

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