Back to FBD referenceTypical FBD symbol for IN
Inputs, outputs, and values
IN
Program input
The IN block represents a program input signal. It has no input ports and emits the current input image value on Q.
Typical FBD symbol
IN
Q
Inputs
| Name | Type | Required | Description |
|---|---|---|---|
| This block has no input ports. | |||
Outputs
| Name | Type | Required | Description |
|---|---|---|---|
| Q | BOOL | Yes | The boolean input value passed into the diagram. |
Stateful
No, the block does not keep internal state.
Behavior rule
Reads the input image value at the scan boundary and passes it to Q.
Practical use
- start pushbutton;
- part-present sensor;
- safety door signal.
What to watch
- Expecting IN to store state by itself. The value comes from the program input image.