Technical data

Programming with STEP 7
Manual, 05/2010, A5E02789666-01 333
16 Configuring Messages
16.1 The Message Concept
Messages allow you to detect, localize, and remedy errors during processing on the programmable
controllers quickly, thus reducing downtimes on a plant considerably.
Before messages can be output, they must first be configured.
With STEP 7, you can create and edit messages linked to events with assigned message texts and
message attributes. You can also compile the messages and display them on display devices.
16.1.1 What Are the Different Messaging Methods?
There are different methods of creating messages.
Bit Messaging
Bit messaging requires the programmer to perform three steps:
• Create the user program on the programming device and set the required bit.
• Create an assignment list using any text editor in which a message text is assigned to the
message bit (for example, M 3.1 = limit switch pressure).
• Create the list of message texts on the operator panel on the basis of the assignment list.
The operator interface system queries the programmable controller cyclically to see whether the
message bit has changed or not. If the programmable controller signals a change, the
corresponding message is displayed. The message receives the time stamp from the operator
interface system.