Use a Sampling Table to collect periodic values from a register (tag) on a TBox RTU. Sampling tables are available only on Analog points.
The values are collected at regular intervals or on an external trigger (this is configured on the RTU). A tag may be configured with more than one Sampling Table. A single Sampling Table is a sequence of one of the following values, calculated over a specified period:
- Instantaneous: The sequence of values of the tag
- Minimum: The minimum value of the series of readings
- Maximum: The maximum value of the series of readings
- Mean average: The average value calculated between two times on a base time of 1 second
- Incremental: The difference between the current value and previously recorded value.
Sampling tables are typically used to capture data on values that change slowly over time, for example, water flow.
A single TBox outstation can have up to 64 sampling tables, and the tables can hold data of type BYTE, WORD or INT. The recording period can be from 1 second to 12 hours, and can also be triggered externally.
Data in a sampling table is not timestamped, but the time of the most recent value is recorded .
A sampling table is distinct from a Sampling Tables. Chronologies are collected on the occurrence of events, typically large changes in a value. You can include both Chronologies and Sampling Tables in a Trend.
In Geo SCADA Expert, in order to retrieve a Sampling Table of instantaneous values, you configure the Analog Point as for a Chronology (see Chronologies).
For other Sampling Tables (minimum, maximum, mean or incremental) you need to:
- Configure a TBox Outstation to correspond to the TBox RTU (see Configuring a TBox Outstation).
- Create a TBox Historical Analog Point.
- Associate the Historical Analog Point with the parent Analog Point that matches the TBox tag for which you want to retrieve the sampling table (see Configuring TBox Historical Analog Points).
- Configure the Historical Analog Point (see Configuring TBox Historical Analog Points).
- Enable historic data logging on the Historic tab of the Historical Analog Point Form (see Defining Historic Details for a Point in the Geo SCADA Expert Guide to Core Point Configuration).
- Select Logged Data in the Historic Data Filter property on the Analog Point tab (see Configuring TBox Analog Points).
- Specify the interval for retrieving historical data from the outstation (see Define the TBox Properties).