Voltages

[Joe]

I'm a novice at this, so please bear with me.. I need to read pressure
using labview and I was wondering what range of voltage should I look
for from a transducer, and should I use anything so that the voltage
won't screw up the DAQ board. Basically it's a very simple
apparatus...hope I get some responses..

[R]

Can you tell us what DAQ board you're using? Alternatively, look in the manual that comes with the board. Richard

[steve.root1]

Pressure transducers typically come in 2 types; bridge and conditioned. The
bridge types use a balanced set of resistors (typically 300R) with the
output being a resistance that changes with pressure. This type needs
either external conditioning or a specialist DAQ bd. But they are a lot
cheaper.

Probly better off using a pre-conditioned transducer, which will have either
a 5(10) VDC or 4-20mA output, and can probably be supplied direct from the
DAQ bd (but check the manual).

Try -
http://www.rdpelectro.com/pressure/menu-pressure.htm
http://www.transtronics.com/reference/xprimer.htm

Hope this helps.

"Joe" wrote in message
news:dd1be3ee.0110241920.16294cf7@posting.google.com...
> I'm a novice at this, so please bear with me.. I need to
read pressure
> using labview and I was wondering what range of voltage should I look
> for from a transducer, and should I use anything so that the voltage
> won't screw up the DAQ board. Basically it's a very simple
> apparatus...hope I get some responses..

[Andrew Buchan]

Simplest form of protection is a Zener diode connected across your signal
inputs (a 10V Zener 'should' chop any signals above 10V - assuming your
using a typical full-scale of an analogue card). Another form of protection
is an isolation amplifier (Analogue Devices ISO124? available from RS) which
should mirror an iput signal to an output, each of which is referenced to a
totally different power supply. This means that even if someone does
something really nasty like connecting a mains live to the earth of your
signal conditioning it shouldn't 'take out' your aquisition board. As you
can probably tell I speak from painfull experience. One word of warning
though - when you're dealing with very small signals the non-linearities of
isolating amps can become signi
ficant.

All the best

Andy

"Joe" wrote in message
news:dd1be3ee.0110241920.16294cf7@posting.google.com...
> I'm a novice at this, so please bear with me.. I need to read pressure
> using labview and I was wondering what range of voltage should I look
> for from a transducer, and should I use anything so that the voltage
> won't screw up the DAQ board. Basically it's a very simple
> apparatus...hope I get some responses..