Siemens SIMATIC NET PROFIBUS Manual de Serviço descarregar pdf (Página 150)

Description of the DP Functions, Data, and Error Codes

DP Base Programming Interface for CP 5613/CP 5614

150

C79000-G8976-C108-01

4.3.4 Checking the Slaves for Changed Data

Uses of the Data Changed Information

The process image of the CP 5613/CP 5614 contains a memory area where you

can see which slave data have changed.

You can use this property to quickly check where data have changed without

having to use semaphores.

Example

"p" is a pointer to the process image that your user program obtained with the

"DP_get_pointer" call. To count, for example, how many slave have changed data,

you would write a program like that shown below, where "sum" contains the result:

unsigned short sum = 0;

unsigned short i;

for (i=0; i < DPR_MAX_SLAVE_ADDR;i++)

{

if ( p->ef.input[i].req_mask == DPR_DATA_CHANGE )

{ /* Changed data found on slave i */

/* Mask released again */

p->ef.input[i].req_mask =

DPR_DATA_INT_CLEAR_AND_UNMASK;

sum++;

}

1 2 ... 145 146 147 148 149 150 151 152 153 154 155 ... 237 238

Sem comentários

Siemens SIMATIC NET PROFIBUS Manual de Serviço Página 150