Technical data

Table Of Contents
SFCs for Global Data Communication
System Software for S7-300/400 System and Standard Functions - Volume 2/2
A5E00739858-01
19-5
Ensuring Consistency for an Entire GD Packet
A GD packet on a receiving CPU has a structure that does not automatically
guarantee that its data originate from one and the same frame. This is, for
example, the case when the packet consists of three GD elements.
If, however, you require consistency for the entire GD packet, follow the procedure
below in your program:
Disable or delay the occurrence of higher priority interrupts and asynchronous
errors by calling SFC 39 "DIS_IRT" or SFC 41 "DIS_AIRT."
Call SFC 60 "GD_SND."
Enable the higher priority interrupts and asynchronous errors again by calling
SFC 40 "EN_IRT" or SFC 42 "EN_AIRT."
Parameter Declaration Data Type Memory Area Description
CIRCLE_ID INPUT BYTE I, Q, M, D, L,
constant
Number of the GD circle into which the
incoming GD packet will be entered. This
number is specified during configuration of the
global data with STEP 7.
Permitted values: 1 to 16. The maximum
number of possible GD circles can be found in
the technical data for your CPU.
BLOCK_ID INPUT BYTE I, Q, M, D, L,
constant
Number of the GD packet in the selected GD
circle in which the incoming data will be
entered. This number is specified during
configuration of the global data by STEP 7.
Permitted values: 1 to 3. The maximum number
of possible GD circles can be found in the
technical data for your CPU.
RET_VAL OUTPUT INT I, Q, M, D, L Error information