First, you need to check if Lookout reads the good value from PLC. If the communication stops or the data has bad quality, Lookout won't log and no data on Hypertrend. So, make sure the communication to PLC is good and data is good during the period when hypertrend shows nothing. For example, if PLC1.data1 stops updating on Hypertrend, check if PLC1.data1 stops updating or red X on it. Also notice if there are any alarms during that time.
Then, go to MAX to see if the data is logged into Citadel. In MAX, create View to display the trend. Check if the data is there or not. If the data is logged, the problem is in Hypertrend. But if there are no trend either in MAX during the gap, it means the logging has problem.
After you create the View, you can "Export to Text". Refer to the attached pic. In the txt file, there are the raw data from Citadel. If there is no data logged during a certain period, you will see the blank in data column.
For example,
183 9:58:26.316 AM 123
184 9:59:37.490 AM 185 9:59:37.490 AM 123
This means from 9:58:26.316 to 9:59:37.490, there is no data logged.
So, we need to check if the data from PLC is good and if the data is logged.
untitled6.JPG:
http://forums.ni.com/attachments/ni/190/5762/1/untitled6.JPG