SPC Chart Trend Alarm Problem

[Former Member]

Hi Experts,

I got a question about the trend alarm function of SPC Chart. The chart is pulling data from a sample history table. Say, with 4000 records. We would like to show 25 points per page in the chart and use the trend alarm to show any trend with 6 consective decreasing points. For example, if we want to show point 1001 to 1025. The trend alarm works great for the points starting from 1006. But is there any way that we can make the first 6 points also alarm on the trend based on the previous record(that is based on 995 to 1000)?

I was thinking to include 6 more points before the group of the data. That is 994 to 1025. Then make point 994 to 999 disappear but I didn't find a way to do it in SPC Chart.

Any suggestion on how to allow trend alarm on all the data points but not starting from the x th points?

Thanks in advanced for the answer.

Best regards,
Lawrence

[Former Member]

Any suggestions is welcome~

[jcgood25]

Really not much the chart can do since alarms are only rendered with the data set provided by the query results, and it would have no visibility to the points leading up to the left edge.  Perhaps documentation/end user training would suffice to tell them that the trending alarms are not rendered at the leading edge of the chart.

If the query is time based then they could easily scroll to the left (back in time) using the toolbar and get the series of points into the main view for further analysis.