Using GPS to Trigger Data Acquisiton
Using the internal GPS built into the LMS SCADAS, one can trigger data acquisition based on:
This can be done in LMS Test.Lab Signature.
Getting Started: Enable GPS
To get started, enable GPS:
Creating a Virtual Channel for the trigger
The next step is to create a virtual logic channel for the trigger. This virtual channel will have a value of "1" when the desired trigger condition is met, and a value of "0" at all other times.
For example, the virtual channel could be a value of "1" if the GPS speed is greater than 19 kph. The virtual channel formula would be "GREATER(gps: Speed;19) to do this. "GPS: Speed" refers to the GPS channel. (Note: There is no space between the ":" and "Speed". The space was added to prevent some browsers from showing emoticons)
Create a virtual channel by selecting the "Virtual Channels" in the upper right corner of the Channel Setup worksheet (Picture 2).
Enter formulas in the Virtual Channels editor to create the desired trigger.
For example, to trigger when speed is between 19 and 21 kilometers per hour, enter the following:
The virtual channel V4 will have a value of "1" when both conditions are met, and can be used for a trigger.
Alternatively, both GPS location and speed can be used (see Picture 3):
Setting a GPS trigger based on both location and speed could be useful to ensure that data is taken over a specific road surface at an exact speed (Picture 4).
Tracking Setup: Setting the Trigger
In the "Tracking Setup" worksheet, use the "Triggered Start" or "Triggered Stop" to set triggers based on the Virtual logic channels (Picture 5).
For more information you can contact your local support.
LMS Test.Lab Acquisition Tips
LMS Test.Lab Displays