SébastienLemaigre
2007-02-01 11:10:14 UTC
Good morning,
We are working on a research project related to biomethanisation. We
have 96 small digestors and we intend to measure the volume of biogas
generated in each of them. The gas flows are very low so we intend to
count gas bubbles in glass tubes filled with colored water.
We have one of these bubble counters
(http://www.ncbe.reading.ac.uk/NCBE/MATERIALS/MICROBIOLOGY/bubblecounter.html)
and we intend to fabric 96.
When a bubble pass in front of the sensor, the voltage pass from 2,25V
to 0,83V and come back to 2,25V. The signal is detected by a LCD
counter (LR 96702). It's an analogic signal, not a square signal and we
know the puse length is above 50 microseconds (detection threshold of
the lcd counter).
We need to regularly acquire (for example each hour) the number of
bubbles generated by the 96 digesters so we want to connect the 96
bubble counters to a DAQ system.
I'd like you help us to choose the more adequate (and low cost)
material for our application and I have several questions to ask :
- Can we use a board with numeric inputs? Are these inputs able to
interpret a sine pulse as a square pulse? Or do we need to transform
the signal?
- Do we need counter inputs? Or is it possible to count the pulses
(detected by classical numeric inputs) in software with labview?
- If we need counters, is NI 7811R a good choice for our application?
- If it is possible to count the pulses in software, is NI 6509 a good choice?
- What cables and terminal blocks do we need? (shielded?)
Thank you in advance for your help.
Sébastien LEMAIGRE
CRP-Gabriel Lippmann
Département 'Environnement et Agro-biotechnologies'
BIOFAR-EVA
41, rue du Brill
L-4422 Belvaux
GD LUXEMBOURG
Tel: +352-47.02.61.458
Fax: +352-47.02.64
e-mail: ***@lippmann.lu
We are working on a research project related to biomethanisation. We
have 96 small digestors and we intend to measure the volume of biogas
generated in each of them. The gas flows are very low so we intend to
count gas bubbles in glass tubes filled with colored water.
We have one of these bubble counters
(http://www.ncbe.reading.ac.uk/NCBE/MATERIALS/MICROBIOLOGY/bubblecounter.html)
and we intend to fabric 96.
When a bubble pass in front of the sensor, the voltage pass from 2,25V
to 0,83V and come back to 2,25V. The signal is detected by a LCD
counter (LR 96702). It's an analogic signal, not a square signal and we
know the puse length is above 50 microseconds (detection threshold of
the lcd counter).
We need to regularly acquire (for example each hour) the number of
bubbles generated by the 96 digesters so we want to connect the 96
bubble counters to a DAQ system.
I'd like you help us to choose the more adequate (and low cost)
material for our application and I have several questions to ask :
- Can we use a board with numeric inputs? Are these inputs able to
interpret a sine pulse as a square pulse? Or do we need to transform
the signal?
- Do we need counter inputs? Or is it possible to count the pulses
(detected by classical numeric inputs) in software with labview?
- If we need counters, is NI 7811R a good choice for our application?
- If it is possible to count the pulses in software, is NI 6509 a good choice?
- What cables and terminal blocks do we need? (shielded?)
Thank you in advance for your help.
Sébastien LEMAIGRE
CRP-Gabriel Lippmann
Département 'Environnement et Agro-biotechnologies'
BIOFAR-EVA
41, rue du Brill
L-4422 Belvaux
GD LUXEMBOURG
Tel: +352-47.02.61.458
Fax: +352-47.02.64
e-mail: ***@lippmann.lu