Hi
I am new in using CSAT3 anemometers with a CR5000 datalogger. I have started using them very recently.
My problem is that I need to connect three CSAT3 with the same datalogger and run simultaneously. So, I figured out I need to use the analog connection. I connected all three CSAT3's through the analog port with CR5000. That worked.
But, how do I go from Ux,Uy and Uz to the wind velocity and direction. Any comments in this regard will be useful, since the probes are non-orthogonal to each other.
Thanks
Arindam
The simplest way to do what you want is to connect all three sensors to the logger using SDM connections. You can theoretically connect up to 15 sensors to one CR5000, although time might be a limiting factor if you did this for fast scan rates.
Connect all three sensors in parallel to the SDM port but make sure the SDM address of each sensor is different. In the program repeat the CSAT3 instruction three times. You can also use the SDM Group trigger command (SDMTrigger) to synchronise the measurements of all the sensors.
This will be quicker and preferable to using the analog outputs, for various reasons, including synchronisation of measurements, resolution and accuracy.
Thank you aps. one question though, how do I know SDM address of each sensors?
Never mind aps...opened the box and found the hex switch..thx
Hi Andrew
By parallel connection, do you mean daisy chain the sonics through a SDM hub. I put all three individual cables from three sonics into same SDM port (three green wires into one port, etc.) and used CSAT3 command three times. I have also changed the HEX address of the sonics. Is this what you mean? Does this configuration has any delay between measurements?
Thanks
You can connect the wires of the same colour into the relevant terminals on the logger (3 wires to a terminal), or we do sell an external hub (just a fancy screw terminal block) where you can common the connections and run one cable back to the logger.
Set the Hex switch to different addresses and match the address to the relevant CSAT3 commands in the program.
If you repeat the CSAT3 command three times with the trigger option in each command there will be a delay between the three successive measurements of ~10 ms or so between the three sensors. However, if you call the Grouptrigger command at the top of the program this instructs all SDM sensors that support this to trigger of one command at that instant. You then put the three CSAT3 commands somewhere below in the program but use the command parameters 97..99 (depending on what data you want). Those parameters tell the logger/sensor to just collect the data previously triggered by the group trigger command.
Please read up about the pipeline delay in the CSAT3 if you are intending to sync these measurements to other sensors though.
are 3 CSAT3 commands really necessary or can one just use reps=3?
Can I attach the analog outputs in a NI module and sample at 5000 Hz. Whatever data I am getting, is that correct? How to know that?