Siemens SIMATIC HMI OP 73micro - Page 67

Mounting and connection
4.4 Communication with S7-200
OP 73micro, TP 177micro (WinCC flexible)
Operating Instructions, 09/2007, 6AV6691-1DF01-0AB0
67
Acknowledgment on the HMI device
The PLC can only detect an error alarm acknowledgment at the HMI device if the "Read
acknowledgment tag" bit is configured. The HMI device sets the "Read acknowledgment tag"
bit in the PLC after it has acknowledged an alarm.
In order to generate a signal transition each time the acknowledgment bit is set, the HMI
device initially resets the corresponding "Read acknowledgment tag" bit when an error alarm
bit is set. There is a certain time-based offset between these two operations due to the
processing time of the HMI device.
The figure below shows the pulse diagram.
1HZ
HUURUDODUP
$FNQRZOHGJP
YLD+0,GHYLFH
5HVHWRI
DFNQRZOHGJPELW
$UULYDORIWKH
HUURUDODUP
$FNQRZOHGJPHQW
+0,GHYLFHᇪ3/&
(UURUDODUP
See also
Overview (Page 127)
Acknowledging an Alarm (Page 134)
Acknowledging an Alarm (Page 131)