IEPE pressure transducer

[uil89]

Hi,

I'm trying to acquire a relative pressure signal via a Dytran 2200V1 IEPE pressure transducer, a cDAQ9189 and a NI 9230.

Since it's not possible to select this type of sensor using Labview which of the following alternatives should I use:

1. Voltage measurement with internal excitation (4 mA) AC coupled

2. Voltage measurement without internal excitation (0 mA) AC coupled

3. Use it as a Microphone 

thanks!

[GerdW]

Hi uil,

I would choose option 1…

[uil89]

Thanks!

Actually I've tried both 1 and 2 but:

Solution 1: as i start the acquisition it takes some time to the sensor to settle, this is fine; howewer sometimes this value is 0.7 mV other times 7 mV; this scaling factor reflects in the voltage to pressure conversion (which one is then the right one?)

Solution 2: the initial value is stable at 0.7 mV but when I start the test I get negative values of voltage; i guess this is because I'm AC coupled. Is this right?

[GerdW]

Hi uil,

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@uil89 wrote:

Solution 2: the initial value is stable at 0.7 mV but when I start the test I get negative values of voltage; i guess this is because I'm AC coupled. Is this right?

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An IEPE sensor needs external current supply, so I wonder you get any signal…

(Here "external" is from point of view of the sensor, it's "internal" to your NI9230 module.)

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@uil89 wrote:

Solution 1: as i start the acquisition it takes some time to the sensor to settle, this is fine; howewer sometimes this value is 0.7 mV other times 7 mV; this scaling factor reflects in the voltage to pressure conversion (which one is then the right one?)

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What about implementing your own "zeroing" aka "tare" feature?

[uil89]

Solution 2: I found this online https://infosys.beckhoff.com/english.php?content=../content/1033/epp3632/4015720203.html&id= 

at "Notes on the IEPE measuring device" it says "In some IEPE measuring devices the supply current can be switched off (0 mA), so that they can be used for voltage measurements", that's why I force the current to 0 mA

[GerdW]

Hi uil,

the datasheet of your sensor doesn't mention this "some" feature. I guess that's more important than the Beckhoff suggestion…

[uil89]

I intended "measuring devices" the NI card, as the Beckhoff ELM3604 is similar to the NI 9230

[uil89]

how would you do the zeroing ?

I'm acquiring at 12.8 kHz, with a reference trigger (1 sec)

thanks again

[GerdW]

Hi uil,

such a zeroing (or tare) is explained several times in the forum.

Just search for "tare feature"…