The “Virtual” data interface provides a function in the I/O manager, which enables virtual, i.e. calculated or linked, signals to be used for acquisition.
Any virtual signals can be created using mathematical and logical operations. These virtual signals can be stored like other measurement signals or used to easily implement complex trigger conditions. Virtual signals enable calculations to be performed during the measurement, for example, calculating totals or differences, checking for tolerance violations, etc.
The procedure for creating virtual signals and a list of available functions can be found in the ibaPDA manual, Part 3 (Interfaces and modules) and Part 4 (Expression builder).
In terms of ibaQDR the virtual signals can be used for a wide range of conversions and adjustments, and even for planning material tracking.
For example, in ibaQDR the virtual signals enable a length measurement signal to be generated from meter pulses.
The following table shows a selection of the functions for calculating virtual signals, which are frequently used in ibaQDR.
|
Function in Expression builder |
Application |
|---|---|
|
OneShot |
Detection of change of condition, value changes, edges; Use as trigger or for reset |
|
INT |
Integral function Calculation of length based on speed |
|
COUNT |
Counting level passes and edges Conversion of meter pulses into length |
|
DELAY |
Delaying a signal by a certain number of acquisition cycles (samples) |
|
DelayLengthL / DelayLengthV |
Dynamic delay of a signal by a distance in length units based on a length or speed signal |
The following chapters contain some application examples.