Technical data

Table Of Contents
Generating Block-Related Messages
System Software for S7-300/400 System and Standard Functions - Volume 2/2
A5E00739858-01
24-7
24.3 Generating Block Related Messages without
Acknowledgement Display with SFB 31 "NOTIFY_8P"
Description
SFB 31 "NOTIFY_8P" represents an extension of SFB 36 "NOTIFY" to eight
signals.
A message is generated if at least one signal transition has been detected. A
message is always generated at the initial call of SFB 31. All eight signal are
allocated a common message number that is split into eight sub-messages on the
displaying device.
One memory with two memory blocks is available for each instance of SFB 31
"NOTIFY_8P". For information on saving signal transitions to intermediate memory
refer to the section "Signal transition detection" in the Introduction to Generating
Block Related Messages with SFBs.
Note
The displaying device shows the last two signal transitions, irrespective of
message loss.
!
Warning
Before you call SFB 31 "NOTIFY_8P" in a CPU, you must insure that all connected
displaying devices know this block. This is the case if at least one of the following
release versions are conditional for the PLC: STEP 7 as V5.1 Service Pack 3,
WinCC as of V5.1 Hot Fix 1, PCS7 as of V5.2 Service Pack 2, SIMATIC Device
Driver as of V5.6.
Otherwise, communication between the PLC and the connected displaying devices
will be shut down. In this case you can no longer access your system with its
connected displaying devices.
Parameter Declaration Data type Memory area Description
SIG_i,
1
i
8
INPUT BOOL I, Q, M, D, L. i-th signal to be monitored
ID INPUT WORD constant (I, Q, M,
D, L)
Data channel for messages:
W#16#EEEE ID is evaluated only at the
initial call.
EV_ID INPUT DWORD constant (I, Q, M,
D, L)
Message number (not permitted: 0)
EV_ID is only evaluated at the first call.
Subsequently, the message number
used for the first call applies to every
call of SFB 31 with the corresponding
instance DB.
STEP 7 assigns the message number
automatically to ensure consistency of
the message numbers. The message
numbers within a user program must be
unique.