Siemens SIMATIC S7-300 Hardware And Installation Manual page 140

Commissioning
VAT structure:
In the VAT, every operand to be monitored or controlled (e.g. inputs, outputs)
occupies one row.
The meaning of the VAT columns is as follows:
Column text
Operand
Symbol
Symbol comment
Status format
Status value
Control value
Monitoring variables
You have two options for monitoring variables:
• updating the status values once via menu item Variable > Update status
values or
• continuous update of status values via menu item Variable > Monitor
Controlling variables
To control variables, proceed as follows:
1. Left-click the field Control value of the relevant variable.
2. Enter the control value according to the data type.
3. To update control values once, select the menu item Variable > Enable
control values .
or
Enable control values permanently via menu item Variable > Control .
4. In the Monitor test function, verify the control value entry in the variable.
Is the control value valid?
You can disable the control value entered in the table. An invalid value is displayed
same as a comment. You can re-enable the control value.
Only valid control values can be enabled.
9-22
This field ...
contains the absolute address of the variable
contains the symbolic descriptor of the variable
This is identical to the specification in the Symbol Table.
shows the symbol comment of the Symbol Table
contains the default format setting, e.g. HEX
You can change the format as follows:
•
Right-click on the format field. The Format List pops up.
or
•
Left-click on the format field until the desired format appears
shows the content of the variable at the time of update
is used to enter the new variable value (control value)
S7-300 Programmable Controller Hardware and Installation
A5E00105492-02