Assignments between data sources and measuring points
What is an assignment?
An assignment connects the raw data from a data source or measurement device with a measuring point. Any number of assignments to different data sources can be made for each measuring point.
An assignment has a start time point and an optional end point. This allows for the range that is of interest to be selected from the raw data of the data source.
Each assignment corresponds to the input channel of a measuring point. An input channel can however be fed from the data of several assignments, which then do not overlap in time.
Depending on the measuring point type, filters, offsets and pre-processing formulae can be defined per assignment.
BEST PRACTICE: Replacing sensors
If a sensor or measurement device malfunctions, then assignments to the defective device should not be deleted, but rather an end date should be set instead.
An assignment with the same name can then be created by the replacement device so that the input channel of the measuring point is retained.
A possible offset can be specified manually or determined automatically.
Advantages
All diagrams, calculations and evaluations remain unchanged despite the sensor being replaced and do not need to be updated.
At the same time, the replacement of the sensor is documented in the assignment table.
Preprocessing measured data
When creating an assignment between a data source and a measuring point, an input channel is created in the measuring point. This input channel provides the raw data to be processed and displayed further within the measuring point.
Depending on the measuring point type, there are different preprocessing options within the assignment properties
Plausibility check
Applies to:
A range can be defined in which the values must lie. Otherwise they are marked as invalid.
Transfer function
Applies to:
Any formula can be defined here, with m1 as the variable for the raw data from the data source.
For example, to specify that a certain fixed offset value is added to each raw data value, the following must be defined as the transfer function:
m1 + <Offset-Value>.
If not specified by the user, the unit of the integrated device channel is automatically added in square brackets after each occurrence of the variable, e.g. for the voltage unit mV:
m1 [mV] + <Offset-Value>.
The offset value must of course be given in the corresponding unit as well.
Raw values from other channels cannot be used at this point. A function block is used to calculate channels together.
If no formula is given when a new assignment is created, the following formula is automatically added:
m1 [<unit of device channel>]
This means that the measured values from the channel flow directly into further processing.
Offset
Applies to: GEODETIC MEASUREMENTS
Entry of offsets for 3D coordinates.
Unit category
Applies to:
When creating an assignment, the category of the unit can be set. Normally the category from the data source is assumed, but should this be incorrect, the category can be overwritten here.
After saving the assignment, the category can no longer be changed.
Unit of result
Applies to:
The channel unit can be changed here.
Filter
Applies to: GEODETIC MEASUREMENTS
A filter for the raw data can be set here.