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Data Acquisition Based on GPS Location

Siemens Theorist Siemens Theorist
Siemens Theorist

Using GPS to Trigger Data Acquisiton


large.jpgLMS ScadasXS with GPS antenna

Using the internal GPS built into the LMS SCADAS, one can trigger data acquisition based on:

  • GPS location - Using latitude and longitude co-ordinates in angle (Picture 1)
  • GPS speed - Speed at which the SCADAS is traveling, typically in kph

This can be done in LMS Test.Lab Signature.


lat_and_long.pngPicture 1: GPS triggers can be based on either latitude or longitude angular positions

Getting Started: Enable GPS


To get started, enable GPS:

  • In "Channel Setup" worksheet, set "Clock sync:" to "GPS" in the upper right corner.
  • In the “Measure” Worksheet, click on the “More…” button. Turn on the checkbox for "Measure GPS Data" and press the "Close" button.

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).


virtual_channel.pngPicture 2: In the upper right corner of Channel Setup Worksheet, select "Virtual Channels" from the pulldown menu.

 Enter formulas in the Virtual Channels editor to create the desired trigger.


Virtual Channel setup

For example, to trigger when speed is between 19 and 21 kilometers per hour, enter the following:


  • V2 - GREATER(gps: Speed;19)
  • V3 - SMALLER(gps: Speed;21)
  • V4 - AND(V2;V3)


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):


  • V1 - GREATER(gps: Latitude;40.3013)
  • V2 - GREATER(gps: Speed;19)
  • V3 - SMALLER(gps: Speed;21)
  • VAND(V2;V3)
  • V5 - AND(V1;V4)


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).


gps_trig_loc_speed.pngPicture 4: GPS location and speed triggers ensure data is acquired on a specific road surface at a uniform speed

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).


Start TriggerFor more information you can contact your local support.


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