System_ioctl block
Short summary
Name |
|
→POU type |
|
Category |
more system blocks, blocks for calling system functions, block with internal error diagnostic |
Graphical interface |
|
Available since |
|
Functionality
The block manipulates parameters of device files or devices via its (file) descriptor. In order to be manipulable, the file descriptor has to be open.
Required expertise In order to use this block efficiently, you have to be familiar with the functionality of the underlying system call for the operating system used on the PLC. |
Inputs, outputs, return value
|
Identifier |
Description |
|
---|---|---|---|
Inputs: |
|
|
the file descriptor |
|
|
the |
|
|
|
additional data for the call |
|
Outputs: |
|
|
return code:
|
|
|
error code returned by the system call Windows standard values (valid for built-in PLC): see https://msdn.microsoft.com/en-us/library/t3ayayh1.aspx |
|
Return value: |
– |
|
returns the return code of the "ioctl" system call in case of Linux Systems |
Input EN
and output ENO
are available when →calling the block. See "Execution control: EN, ENO" for information on input EN
and output ENO
.
See:
-
"Blocks for safe logic" whether this block is supported for developing safety-relevant applications.
-
"Highlighting safe logic in the FBD-editor" for the effects when using the block as a block for safe logic.
Internal error diagnostic for block
The block checks the following error cases:
-
The system service has not been loaded.
-
The return value of the block is a negative value.
-
The return code of the function call equates to an error (output
rc
≠ value0
).
In such an error case, the output ENO
of the block is set to value FALSE
(or an equivalent).
Example for usage within ST-editor
At present, there is no example.