Corrected from:
PLC Designer V3.15
Response of the new version:
Question marks at the inputs and outputs of blocks can be easily deleted in the FBD editor. No exception will be displayed.
What happens?
The following exception appears when question marks are deleted:
Object reference not set to an instance of an object
When does this behaviour occur?
The behaviour occurs if in the FBD editor the ('???') question marks at inputs, outputs or in the instance names of blocks are deleted by means of the <Del> or the reset key (<←> key) and after this the <↑> or the <↓> arrow keys are used to go to the next element (e.g. input or output).
Which products are affected?
PLC Designer from V3.14
Short-term measures:
After deleting the question marks, use the mouse to go to the next input / output.
Go to the 'Options' dialog (menu command Tools>Options) and activate the 'Empty operands for' option in the 'General' register in the 'FBD, LD and IL' category. In this way, no question marks will be written at inputs and outputs when inserting blocks in a network.
Evaluation/recommendations:
By default, question marks are written at the inputs and outputs of a block when inserting a block in the FBD editor. If the question marks are deleted and the cursor is moved by means of the arrow keys after this, an exception will occur. A remedy is described under 'Short-term measures'.
