Rockwell Automation 1771-DMC_DMC1_DMC4_DXPS Control Coprocessor User Manual - Manual (Page 206)

API Library of Routines
Appendix B
DTL_RMW_W_IDX
B-75
Invalid Definition Example
DTL_C_DEFINE (&idl, “N34:3”) /* not specified to element 0 */
DTL_C_DEFINE (&idl, “N34:0,3,long”) /* number of items not 1 */
C Example
/*
* Suppose there are 5 16-bit “status words” in binary file 10, elements
* 0 through 4, each describing the current status of 5 machines. Bits
* 0 through 3 of each word contain a code for the “current mode” (0-F)
* of the machine. This example changes the “current mode” to a value
* of 2 without modifying bits 5-31 for machines 0 and 4.
*/
#define MODE_AND_MASK 0xFFF0 /* preserve bits 5-31 */
#define MODE_OR_MASK 0x0002 /* set bit 1*/
#define MAC_0 0x0000 /* machine 0 index */
#define MAC_2 0x0004 /* machine 4 index */
unsigned id;
unsigned iostat;
DTL_C_DEFINE (&id, “B10:0, 1, WORD, MODIFY”);
DTL_RMW_W_IDX (id, MODE_AND_MASK, MODE_OR_MASK, &iostat, MAC_0);
DTL_RMW_W_IDX (id, MODE_AND_MASK, MODE_OR_MASK, &iostat, MAC_4);
BASIC Example
The BASIC function code is 22.
procedure COPRO
DIM status : INTEGER
DIM id : INTEGER
DIM iostat : INTEGER
DIM and_mask : INTEGER
DIM or_mask : INTEGER
rem * Define the data file
RUN AB_BAS (2, status, ADDR(id), “B10;), 1, LONG, MODIFY”)
and_mask := $FFF0
or_mask := $2
RUN AB_BAS (22, status, id, and_mask, or_mask, ADDR(iostat), 0))
RUN AB_BAS (22, status, id, and_mask, or_mask, ADDR(iostat), 4))
References
DTL_C_DEFINE(); DTL_READ_W_IDX();
DTL_WRITE_W_IDX();