FBD/LD/IL editor in online mode
In online mode, the editor displays the current value of each variable after the variable name. Writing/forcing and setting breakpoints is possible.
If the variable is currently forced, this is indicated by 
directly in front of the forced value. If a value is prepared for writing or forcing, this value is displayed in parentheses <value> immediately after the current value.
Example:
Forced variable:
Prepared value
In the online view of a Ladder Diagram (LD), the connection cables are color-coded: Connections with the value TRUE are displayed as a bold blue lines, connections with the value FALSE as a bold black lines. Connections of unknown or analog value are displayed normally (thin black line).
 | Note that the value of the connections is calculated from the monitored variables. This is not a real process control. |
Breakpoints
Possible locations for breakpoints are the positions where variable values can change (instructions), where the program branches, or where an another function block is called.
Possible breakpoint positions:
- On the entire network: Causes the breakpoint to be set at the first available position in the network.
- On a function block box, if the function block contains an assignment. Not possible for operator function blocks, for example ADD, DIV.
- At assignments.
- At the end of the function block at the position of the return to the calling function block. In online mode, an empty network automatically appears at this point, which is marked with "RET" instead of a network number.
| At present, you cannot set a breakpoint directly on the first function block in the network. However, if you set a breakpoint on the entire network, this breakpoint marker is automatically transferred to the first function block in online mode. |
| Breakpoints in methods: TwinCAT automatically sets a breakpoint in all methods that can be called. This means that if a method managed by an interface is called, breakpoints are set in all methods that occur in function blocks that implement this interface, as well as in all derived function blocks that use the method. If a method is called via a pointer to a function block, TwinCAT sets the breakpoints in the method of the function block and in all derived function blocks that use the method. |
See also: