Siemens LOGO!, Manual

Page: 235 / 534

LOGO! functions
4.4 Special functions list - SF
LOGO!
Manual, 04/2011, A5E03556174-01
235
Restriction
A maximum of 50 message texts are available.
Functional description
When LOGO! is in RUN mode, LOGO! displays the message text that you have configured
along with its parameter values upon a 0 to 1 transition of the signal at input En.
Based on your setting for the message destination, the message text displays on the
LOGO! onboard display, the LOGO! TD, or both.
If you use flag M27 in your circuit program, then if M27=0 (low) then LOGO! displays the
message text only if it is from the primary character set (Character Set 1). If M27=1 (high),
then LOGO! displays the message text only if is from the secondary character set (Character
Set 2). (See the M27 flag description in topic Constants and connectors - Co (Page 138)).
If you have configured message ticking, the message will tick on and off the display
according to your specifications, either a character at a time, or a line at a time.
If acknowledgment is disabled (Ack = Off), the message text is hidden when the status of the
signal at input En changes from 1 to 0.
If acknowledgment is enabled (Ack = On) and the status of the signal at input En changes
from 1 to 0, the message text is output until it is acknowledged with OK. When En = 1, you
cannot acknowledge the message text.
When multiple message text functions are triggered with En=1, LOGO! displays the message
text with the highest priority (0 = lowest, 127 = highest). This also means that LOGO!
displays a newly activated message text only if its priority is higher than that of previously
activated message texts.
After a message text is disabled or acknowledged, the function automatically shows the
previously active message text that takes the highest priority.
You can press the and keys to step through multiple active message texts.