Test and Measurement Forum

Rocket Test Stand

Which product is right for your exact requirements

Rocket Test Stand

Postby Guest » Thu Nov 27, 2008 10:35 pm

I need a data acquisition system for a rocket test stand i am designing. Pressure ranges are between 0 - 10Mpa and Thrust between 0 - 200N. Rockets are for a lab only, they are very small (4cm diameter and 7 cm long). I chose a pressure sensor and a load cell from Tecsis, i haven't bought anything though. If this sensors are not compatible, maybe you could recommend some that are. Furthermore, the combustion lasts between 1 and 2 seconds, so i need the system taking enough samples in such a small time

Please I really need help with this, thanks for your time
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Postby ziko » Mon Dec 01, 2008 3:35 pm

Hi,

This may be possible there are a number of things you need to establish:

1) What the output of the transducer is
2) How quick you want to sample the data.
3) Length of time (you said 1 or 2 seconds)
4) What resolution you require from the transducer

Once I have this information I will be able to tell which product is most suitable. Using our data logging software you can record a block of data on a trigger event and store it on the computer.

Kind regards
Ziko

Technical Specialist
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Postby Guest » Tue Dec 02, 2008 12:53 am

Hello,

Thanks for your reply. I'm posting some of the technical data of the transducers, hope it's useful to figure out what AS is suitable.

Force transducer:

Analogue output
- Output signal 0.8 ... 1.2 mV/V
- Bridge resistance 350 Ω
- Option Cable integrated amplifier 0 (4) … 20 mA,
0 … 10 V DC
- Tolerance of span ≤± 0.1% of F.S.
- Excitation voltage 2 … 8 V (max. 8 V), 16 … 32 V DC
for cable integrated amplifier
- Electrical connection Cable 3 m / 4-wire


Pressure sensor

Output signal 4...20 mA - 2-wire system
0...5 VDC - 3-wire system
0...10 VDC - 3-wire system

About the length of time the critical conditions depend on the nozzle and propelant i'm using, which for this case are: 0 - 1.2 sec and 0 - 2.5 sec

What i need exactly is getting the Pressure/Time and Thrust/Time curves, so i need enough points to get a sufficiently smooth curve let's say a minimum of 30 points (i know that industrial rocket test stands may reach a res of more than 3000 points per second, if there's a chance of getting even close to a fraction of it, it'd perfect)

Thanks again
Guest
 

Postby PeterF » Fri Dec 05, 2008 12:24 pm

Hi,
I am sure we can help here. The pressure and force transducers seem fine. We can log from any of the outputs mentioned, 0-5V or 0-10V probably the easiest. If you only require 8 bit analogue resolution (256 steps of pressure or force) you can use our entry level 2203 scope:-
http://www.picotech.com/ultracompact-oscilloscopes.html
If (as you probably do) need 12 bit resolution (4096 steps) you need our 3224 scope:-
http://www.picotech.com/pc-scope.html
Either scope can take samples of each parameter at a rate of 1 million samples per second for two seconds or 333 thousand samples for 5 seconds. The results can be displayed and saved as a single data file and also exported to Matlab4 or Excel. Our PicoScope6 software is free. Since the capture time is so short there is no need to use the PicoLog software so capture rates can be high.
Please contact again if you need more information.
Regards,
PeterF.
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