In the Function Block Diagram, breakpoints can only be set to networks. If a breakpoint has been set to a network, then the network numbers field will be displayed in blue. The processing then stops in front of the network where the breakpoint is located. In this case, the network numbers field will become red. Using stepping (single step), you can jump from network to network⮫ “The 'Resources' tab”.

The current value is displayed for each variable. Exception: If the input to a function block is an expression, only the first variable in the expression is monitored.

Doubleclicking on a variable opens the dialog box for writing a variable. Here it is possible to change the present value of the variable. In the case of Boolean variables, no dialog box appears; these variables are toggled.

The new value will turn red and will remain unchanged. If the 'Online' 'Write values' command is given, then all variables are placed in the selected list and are once again displayed in black⮫ “'Online' 'Write values'”.

The flow control is started with the 'Online' 'Flow control' command Using the flow control, you can view the present values that are being carried in the networks over the connecting lines⮫ “'Online' 'Display flow control'”. If the connecting lines do not carry Boolean values, then the value will be displayed in a specially inserted field. If the lines carry Boolean values, then they will be shaded blue in the event that they carry TRUE. By this means, you can accompany the flow of information while the PLC is running.

If you place the mouse pointer briefly above a variable, then the type, the address and the comment about the variable will be displayed in a Tooltip.