memioReadX (Function)

memioReadX works similar to memioRead but allows access to multiple elements in one highly efficient operation.

The use of memioReadX is recommended in cases where a range of memory I/O locations must be read sequentially.

Also see memioWriteX.

Input:

index : INT (1..4096)

Memory I/O system Index number where the read operation will start.

mem : PTR

Address to write the data that will be read from the memory I/O area.

len : INT

Number of 32-bit elements to be read from the memory I/O area.

Returns: INT

Declaration:

FUNCTION memioReadX : INT;
VAR_INPUT
  index : INT; // index to read from (1..4096).
  mem   : PTR; // address to read from.
  len   : DINT; // number of elements to read.
END_VAR;

Example:

INCLUDE rtcu.inc
 
PROGRAM test;
VAR
  buffer : ARRAY[1..10] OF DINT;
END_VAR;
 
...
 
// Read 10 elements directly from I/O space starting at location 120, and place the data into 'buffer':
memioReadX(index:=120, mem:=ADDR(buffer), len:=10);
 
...
 
END_PROGRAM;