Displaying Messages; Displaying Messages With/Without Variables - Siemens SIMATIC S5 TD 390 Manuel

6

Displaying Messages

6.1

Displaying Messages With/Without Variables

Messages Messages (with or without process, timer and counter values) are
displayed. However, you cannot modify any of the values in this
operating mode ("Display Messages") using the TD. The messages are
stored in the text DBs 1 to 5 (see Section 8.4). Three flag bytes
containing a total of 24 flag bits (one bit for each message) are assigned
to each message DB in the corresponding DB (see Section 8.3).
Conditions The following conditions apply for enabling the display of messages on
for displaying the TD:
messages
After the self–test, the "Display Messages" operating mode (basic
mode) is set. Messages are immediately displayed if flag bits are set.
Since the flag bits for timers and counters have a higher priority,
timer/counter values may be displayed.
The display always starts the valid parameters with the first text DB.
It is not important when the flag bits were set by the program.
All messages whose flag bits are set are transferred from the PLC to
the message buffer of the TD 390. When the message buffer is fully
built up, it is displayed.
In accordance with the scan time interval selected (parametric DB or
default), the messages are read out of the PLC and updated in the TD
message buffer. This is the minimum scan time. The scan time may
be greater if the data volume is large (display several messages simul-
taneously).
Messages whose flag bits are reset are removed from the message
buffer.
TD 390
C79000–K8576–C292–01
6-1