Siemens SIMATIC HMI 177 Operating Instructions Manual page 94

Appendix
A.2 Evaluation of the operator control elements
7. Select the system function "SetValue" from the "Calculation" group. Select the
8. When communication is established, the possibly old value currently existing in the
9. A program in the PLC evaluates the live bit. After the control program has determined
10. Click "Change value" in the properties window of the "Auxiliary_Tag" tag in the "Events"
11. Select the system function "SetValue" from the "Calculation" group. Select the
Result
The values for the operator control elements are consistent between operator control
element, HMI device and PLC.
A-12
"Control_Element_PLC" tag at "Tag (output)". Select the "Status_Control_Element" tag at
"Value".
controller is then written automatically into the "Control_Element_PLC" tag. The "Auxiliary
Tag" is required for transfer of the current status of the operator control element to the
PLC.
that communication has been established, the control program changes the current value
of the "Auxiliary_Tag" tag once in order to induce a change in value. The value change in
the "Auxiliary_Tag" triggers performance of the "SetValue" system function. The system
function assigns the value of the "Status_Control_Element" tag again to the
"Control_Element_PLC" tag. In order to configure the system function, open the
properties window of the "Auxiliary Tag".
group. The "Function list" dialog box appears. Click the first line of the function list. The
list opens, showing the available project functions.
"Control_Element_PLC" tag at "Tag (output)". Select the "Status_Control_Element" tag at
"Value".
Mobile Panel 177 (WinCC flexible)
Operating Instructions (Compact), Edition 07/2005