Technical data

Table Of Contents
SFCs for Global Data Communication
System Software for S7-300/400 System and Standard Functions - Volume 2/2
19-2
A5E00739858-01
Ensuring Consistency for an Entire GD Packet
A GD packet on the CPU sending the data has a structure that does not
automatically guarantee that the collected data are consistent. This is, for example,
the case when the packet consists of an array of bytes and the number of bytes
exceeds the maximum length for the specific CPU.
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 in which the GD
packet to be sent is located. You specify
this
number when configuring 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 of your CPU.
BLOCK_ID INPUT BYTE I, Q, M, D, L,
constant
Number of the GD packet to be sent in the
selected GD circle. This number is set
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 of your CPU.
RET_VAL OUTPUT INT I, Q, M, D, L Error information