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Overview of the DP Base Interface

DP Base Programming Interface for CP 5613/CP 5614

C79000-G8976-C108-01

Elements of a Polling Cycle

All the steps described below are achieved by direct access to the process image

using the C pointer as the result of the "DP_get_pointer" call.

Taken together, they represent an example of a polling cycle.

Step Action Meaning

1 Check the mode of the

master in the process

image (USIF_state,

Section 4.3.6)

Input data are only valid in the

OPERATE and CLEAR modes. Output

data can only be sent in the OPERATE

mode.

Check the state of the

slaves in the process

image (slave_state,

Section 4.3.5)

Communication functions only when

the slaves are in the READY mode.

3 Optional: Check whether a

slave has changed data

(req_mask, Section 4.3.4),

If yes: reset req_mask

Your user program can recognize

whether or not input data from a slave

has changed.

4 Read input data of the

slaves (slave_in[ ].data,

Section 4.3.1),

consistency by accessing

D_lock_in_slave_adr

For further processing in the user

program

Check new diagnostic

data of the slaves

(diag_count, Section

4.3.2)

If the diagnostic counter has changed

since the last cycle, there is new

diagnostic data.

6 If applicable, read

diagnostic data of the

slaves (slave_diag[ ].data,

Section 4.3.2),

consistency by accessing

D_lock_diag_slave_adr

For further processing in the user

program

7 Write output data of the

slaves (slave_out[ ].data)

As the result of processing the input

and diagnostic data

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