Sampling Types
- Interpolated Sampling
- Calculates values between two data points using a linear inter- polation algorithm.
- Calculated Sampling
- Computes values using an algorithm selected in the Calculation field.
- Lab Sampling
- Computes intermediate values between two data points by using the last actual value. This type of sampling displays as a stair step type of curve.
- Trend Sampling
- Returns the raw minimum and raw maximum value for each specified interval. Use the Trend sampling mode to maximize performance when retrieving data points for plotting. For the Trend sampling mode, if the sampling period does not evenly divide by the interval length, Historian ignores any leftover values at the end, rather than putting them into a smaller interval.
- InterpolatedtoRaw Sampling
- Provides raw data in place of interpolated data when the number of samples fall lesser than the available samples.
- TrendtoRaw Sampling
- The TrendtoRaw sampling mode almost always produces the same results as the Trend sampling mode. The exception is that, when more samples are requested than there are raw data points, the TrendtoRaw sampling mode returns all of the available raw data points with no further processing. TrendtoRaw is therefore used rather than Trend when the number of actual data samples are fewer than the requested number of samples.
- LabtoRaw Sampling
- Provides raw data for the selected calculated data over the plot, when the number of samples fall lesser than the available samples.
- RawByFilterToggle Sampling
- Returns filtered time ranges with values 0 and 1. If the value is 1, then the filter condition is true and 0 means false. This sampling mode is used with the time range and filter tag conditions. The result starts with a starting time stamp and ends with an ending timestamp.
- Trend2 Sampling
- Returns the raw minimum and raw maximum value for each specified interval. Use the Trend2 sampling mode to maximize performance when retrieving data points for plotting. Also, if the sampling period does not evenly divide by the interval length, Historian creates as many intervals of the interval length as will fit into the sampling period, and then creates a remainder interval from whatever time is left. Trend2 sampling mode is more suitable than Trend sampling mode for analysis of mins and maxes and for plotting programs that can handle unevenly spaced data.
- TrendtoRaw2 Sampling
- The TrendtoRaw2 sampling mode almost always produces the same results as the Trend2 sampling mode. The exception is that, when more samples are requested than there are raw data points, the TrendtoRaw2 sampling mode returns all of the available raw data points with no further processing. TrendtoRaw2 is therefore used rather than Trend2 when the number of actual data samples are fewer than the requested number of samples.