DSC False Alarm and NO Memory record

[martipe1]

I have a DSC 1832 security system, lately I have had a few false alarms, when I check out the keypad it shows Memory label, but when I press * 3 # I see no record of the sensor who triggered the alarm.
 
What can I do to know what sensor triggered the alarm and be able to correct false alarms?
 
Thanks in advance for your help