Rockwell Automation 1771-DMC_DMC1_DMC4_DXPS Control Coprocessor User Manual - Manual (Page 136)

API Library of Routines
Appendix B
BPI_READ
B-5
Responds to a synchronous block-transfer write from a
programmable controller.
Important: Only a single task should use the BPI functions. A second
calling process is put to sleep if the BPI is already in use. The second task
could time out unexpectedly.
C Syntax
#include <copro.h>
unsigned BPI_READ (size,dst,timeout,trg_mask)
unsigned char size;
short *dst;
unsigned int timeout;
unsigned short trg_mask;
Parameters
size
Determines how many words the programmable controller
will send.
dst
Provides the address of the buffer where the data is stored that the
programmable controller will send.
timeout
The function timeout in seconds. The application program stops until
the function completes or times out. A value of 0 causes the function to
use the minimum value of 1 second. The maximum value is TOMAX
(0x 3fff).
trg_mask
Use this word mask to inform a programmable controller to initiate a
block-transfer write to the control coprocessor. The ladder-logic
program in the programmable controller monitors this mask as a
condition to trigger the block transfer. The bit mask is the actual
input-image word for the rack and slot location of the control
coprocessor. If the parameter is null, then it won’t attempt to send the
bit mask to the programmable controller before the BPI_READ.
BPI_READ