Which products are affected?
ESP-HMI1-P (HMI Designer V1.6 and higher)
EPM-H502 (Touch screen)
What happens?
Alarm messages (= Alarm history) can be saved for tracing purposes in the alarm buffer. That means that in case of every alarm message, the alarm buffer saves the time when the message occurred, when it was acknowledged and when it was deleted. Under the Alarm messages project component it can be set for every alarm message whether it is to be saved in the alarm buffer. The alarm buffer can be saved in a mode protected against mains failure.
If command code 45 (save alarm history) is activated via the command area of the keypad, this command is detected and acknowledged but it is not executed. This means that the alarm buffer is not saved with mains failure protection against mains failure by command 45.
When does the problem occur?
The alarm buffer cannot be saved with mains failure protection via the command area of the keypad.
This function restriction only affects the H502 keypad.
Possible diagnostics?
None.
Short-term measures/recommendations?
Under the Alarm back-tracing register of the Project settings dialog (menu item Configuration>Project settings) the smallest possible Auto Save Interval (e. g. 2 hours) is to be set. Thus the keypad automatically saves the alarm buffer after expiry of the Auto Save Interval.
Evaluation:
A keypad can be controlled by a superimposed PLC via the command area. The command for saving the alarm buffer is not executed by the H502 keypad. However, the alarm buffer is principally either saved after expiry of the Auto Save Interval or at a specific time.
