F_IOPortRead
![F_IOPortRead 1:](Images/png/9007199286084363__Web.png)
A digital I/O port is usually an I/O position with a width of 1 byte, which is mapped either in the memory or as a port. If a value is written at this point, the electrical signal at the output pins is modified according to the written bits. If a value is read from the input position, the current logical level at the input pins is returned as an individual bit value.
The function F_IOPortRead can be used to read an I/O position with a width of eSize. The function returns the read value as return parameter. See also description of the F_IOPortWrite function.
FUNCTION F_IOPortRead : DWORD
Inputs
VAR_INPUT
nAddr : UDINT;
eSize : E_IOAccessSize;
END_VAR
Name | Type | Description |
---|---|---|
nAddr | UDINT | I/O port address |
eSize | E_IOAccessSize | Number of data bytes to be read (type: E_IOAccessSize) |
Requirements
Development environment |
Target system type |
PLC libraries to include (Category group) |
---|---|---|
TwinCAT v3.1.0 |
PC or CX (x86, x64, ARM) |
Tc2_System (System) |