05-22-2014 11:03 AM
Hi,
I'm working on a project that requires a real-time torque measument on a three phase motor-gearbox-shaft configuration.
I have the SCXI-1520 module and I'm thinking about using a strain gauge with a full-bridge configuration to do this.
The problem is that it's not possible to wire everything for a real time measure, so my first solution was using some kind of wireless transmission to receive the data into the SCXI-1520
The Arduino+Xbee seems to be the cheapest way to go, but at the same time I think I might have some problems conditioning the signal while transmitting the data to LabVIEW through the SCXI-1520.
Do you think is this the best way to do it or is there any better solution?
Thanks!
Solved! Go to Solution.
05-23-2014 10:21 AM
Hi kennycaldas,
Can you describe a little more thoroughly how you plan on connecting your SCXI card, DAQ card, and Xbee? You are correct that you will most likely run into issues obtaining a truly deterministic signal with this method if you are planning on sending the signal through your RT Operating System. Do you have a Real-Time Controller you can use following this KnowledgeBase article?
How Do I Configure My SCXI Chassis for a Real-Time Target in MAX? : http://digital.ni.com/public.nsf/allkb/155924F3CE83E2C2862571F1006E5532?OpenDocument
Additionally, you may try considering WirelessHART because it is better designed for RT measurements.
Regards,
Anna L
05-23-2014 11:20 AM
Hi Anna,
My first thought was having the Arduino attached to the shaft, wired to the strain gage and some kind of OP Amp, to improve the signal a little.
On top of the Arduino would be connected the Xbee, which would be providing the wireless communication to the SCXI 1520, through some kind of receiver, like Xbee Explorer for example.
After this, I could interpreted the data using LabVIEW.
Another way that I thought of using was having the Arduino+Xbee configuration described above, but without the SCXI 1520. instead, the Arduino would be communicating directly with
LabVIEW using the Arduino's add-on LIFA.
Not sure which would be the best configuration, trying to figure out before actually start buying the right components.
The RT measurement is an important part of this project, and I can't use the SCXI 1520 directly wired to the strain gage on the shaft because of the wire lenght limitation.
Any ideas?
Thank you!
Kenny
05-27-2014 04:45 PM - edited 05-27-2014 04:55 PM
Hi Kenny,
What kind of operating system are you using? When you say "Real-Time," do you mean viewing the signal as it occurs? If you are using network communication, you won't be able to get truly real-time control because network communication is not deterministic and you cannot guarantee the timing.
If you are trying to obtain a signal and view it as you are acquiring it, you should be able to use the Arduino and LIFA with LabVIEW. Adding the SCXI 1520 will not add any extra resolution in this circumstance.
Best regards,
Anna L
05-29-2014 02:56 PM
Hi Anna,
Yes, I was thinking exactly about it, if the SCXI-1520 would increase in some way the resolution of my measurement.
But since it's not, I think I'll go with the Arduino+LIFA combination only to collect the data.
Thank you!