The trend buffers reside in the NAE and store the trend samples for the NAE. The number of samples stored in each individual trend buffer is user-configurable (see Trend Extension Attributes). When the buffer gets full, you can choose to have the new trends overwrite the old ones or to have the trending stop. Whether the trends are overwritten or trending stops, you can configure the system to issue an alarm when the buffer gets full. You can also configure to transfer samples to a configured ADS , or OAS.
Table 1 shows the relationship between the buffer size and the sample interval. Determine the sample interval, in seconds, by converting minutes to seconds. Determine the buffer size by examining the interval, in seconds, against the desired time period size to retain data.
|
Interval (Min.) |
Interval (Sec.) |
Buffer for Previous Time Period |
|||||||
|---|---|---|---|---|---|---|---|---|---|
|
1 Hr. |
2 Hrs. |
4 Hrs. |
8 Hrs. |
16 Hrs. |
1 Day |
2 Days |
3 Days |
||
|
1 |
60 |
60 |
120 |
240 |
480 |
960 |
1,440 |
2,880 |
4,320 |
|
2 |
120 |
30 |
60 |
120 |
240 |
480 |
720 |
1,440 |
2,160 |
|
5 |
300 |
12 |
24 |
48 |
96 |
192 |
288 |
576 |
864 |
|
10 |
600 |
6 |
12 |
24 |
48 |
96 |
144 |
288 |
432 |
|
15 |
900 |
4 |
8 |
16 |
32 |
64 |
96 |
192 |
288 |
|
30 |
1,800 |
2 |
4 |
8 |
16 |
32 |
48 |
96 |
144 |
|
60 |
3,600 |
1 |
2 |
4 |
8 |
16 |
24 |
48 |
72 |
|
120 |
7,200 |
1 |
2 |
4 |
8 |
12 |
24 |
36 |
|