Technical data

Configuring Messages
16.1 The Message Concept
Programming with STEP 7
Manual, 05/2010, A5E02789666-01 341
16.1.6 Formal Parameters, System Attributes, and Message Blocks
Formal Parameters as Message Number Inputs
For each message or group of messages you need a formal parameter in your program that you
specify as the IN parameter in the variable overview of your program. This formal parameter is then
used as a message number input and forms the basis of a message.
How to Provide Formal Parameters with System Attributes
As a prerequisite for starting message configuration, you must first provide the formal parameters
with system attributes as follows:
1. Add the following system attributes for parameters: "S7_server" and "S7_a_type"
2. Assign values to the system attributes corresponding to the message blocks that you called in
your program code. The value for "S7_server" is always "alarm_archiv", the value for
"S7_a_type" corresponds to the called message block.
System Attributes and Corresponding Message Blocks
The message blocks themselves are not displayed as objects in the message server; instead, the
display contains the corresponding values of the system attribute "S7_a_type". These values have
the same names as the message blocks that exist as SFBs or SFCs (exception: "alarm_s").
S7_a_type Message Block Description Properties
alarm_8 ALARM_8 SFB34 8 channels, can be acknowledged, no associated
values
alarm_8p ALARM_8P SFB35 8 channels, can be acknowledged, up to 10
associated values per channel
notify NOTIFY SFB36 1 channel, cannot be acknowledged, up to 10
associated values
alarm ALARM SFB33 1 channel, can be acknowledged, up to 10
associated values
alarm_s ALARM_S SFC18 1 channel, cannot be acknowledged, up to 1
associated value
alarm_s ALARM_SQ SFC17 1 channel, can be acknowledged, up to 1 associated
value
ar_send AR_SEND SFB37 Used to send an archive
notify_8p NOTIFY_8P SFB 31 8 channels, cannot be acknowledged, up to 10
associated values
alarm_s ALARM_DQ SFC 107 1 channel, cannot be acknowledged, up to 1
associated value
alarm_s ALARM_D SFC 108 1 channel, cannot be acknowledged, up to 1
associated value
You will find more detailed information in the reference online help on system attributes.