Our users often ask us to differentiate between the terms "raw data channel" and "calculated" or "virtual data channel". We think it is important that you take a moment to familiarize yourself with the inherent different between the two - they each have very specific purposes!
Raw data channel
- Contains unmodified data sourced from an instrument in the field or an imported data file.
The type of data contained in a raw channel is dependent on the sensor or meter in the field. For example, the data could be the rate of flow, inches of rain, or even the voltage of a battery. FlowWorks collects these data values along with date and time stamps and 'stores' them in raw channels that can be referenced in any of FlowWorks' Graphing, Reporting and Analysis tools.
The channel name displayed in FlowWorks may be limited by the communications methodology used to forward data to FlowWorks. A portion of the system security tests require that the data arrive bearing the configured channel name. Thus, if you are conveying your data by FTP, the displayed raw channel name will need to be the same as that of which is contained in the data packet. If your data comes from a Telog logger, you may be able to map the Telog channel name to a different name used in FlowWorks. This will allow you to use a channel name in FlowWorks that is easy to recognize. Other instrument manufacturers; and differences within the models of a manufacturer; may enhance or limit your ability to create unique raw channel names. For the most part, users have traditionally chosen to use the names commonly generated by the field equipment.
Calculated (virtual) data channel
- A virtual stream of data points whose source is a raw data channel to which F.A.C.E. math, F.A.C.E. conditional statements, and/or F.A.C.E. functions have been applied to adjust raw data values. data originating from a Raw Channel; or to create information which was not directly available from the field instrument (such as flow when the instrument only supplies depth and velocity).
It is important that FlowWorks does not support modifications to raw channels so that a working backup of raw data can remain available at all times. However, with the use of F.A.C.E. you can create a calculated channel that consistently copies-in data from the original channel and applies a desired conversion function or formula. The resulting data contained in the calculated channel can be used in any of FlowWorks' graphing, reporting and analysis tools in lieu of the original channel. The original channel is left untouched as a back-up, or if you want to create further calculated channels using the same data.