Use of BNC converter to screw terminal for module NI 9215

[GerardoGuzman]

Hi, I wanted to know if anyone has an idea if it is possible to use the adapter attached in the image to convert a BNC signal to a two-wire terminal (positive and negative) and use it in a 9215 module ( I have screw terminal module, NO ! BNC entrance type). I have this doubt because I am doing a project of analysis of vibrations and the accelerometers that are intended to use are like the one shown in the page of Natinal Instrument and of which I attach an image also, they bring a cable type BNC with male termination (I already have the female plug in the image adapter) and my module does not accept this type of connector in the input (see image) so as a solution I thought of using a signal adapter that would convert BNC to a positive and negative signal but I have no idea if this can affect much to the signal that is introduced in the module 9215 or in the own LabView would not be able to make a suitable analysis of the signal coming from the accelerometer. Thanks for helping me.

[GerardoGuzman]

Hola, queria saber si alguien tiene una idea de si es posible llegar a utilizar el adaptador que adjunto en la imagen para convertir una señal de BNC a un terminal de dos cables (positivo y negativo) y este utilizarlo en un modulo 9215 (con terminales de tornillo y NO de tipo BNC). Tengo esta duda dado que estoy haciendo un proyecto de analisis de vibraciones y los acelerometros que se pretender usar son como el mostrado en la pagina de Natinal Instrument y del cual adjunto una imagen tambien, estos traen un cable tipo BNC con terminacion macho (ya tengo el acople macho hembra en el adaptador del imagen)  y mi modulo no acepta este tipo de conector en la entrada (ver imagen) por lo cual como solucion pense en utilizar un adaptador de señal que me convirtiera BNC a señal de tipo positivo y negativo pero no tengo idea si esto puede afectar mucho a la señal que se introduzca en el modulo 9215 o en el propio LabView no lograria poder hacer un analisis adecuado de la señal proveniente del acelerometro. Gracias de antemano por ayudarme.

[GerdW]

Hi Gerardo,

if it is possible to use the adapter attached in the image to convert a BNC signal to a two-wire terminal and use it in a 9215 module.

Yes, sure.

What is a "BNC signal"? BNC usually only describes the connector type…

I have no idea if this can affect much to the signal

Define "much"!

Each and every adaptor introduces signal changes as it acts as a (kind of) filter - you have to decide  if you can live with those changes…

[GerardoGuzman]

Hi GerdW i really appreciate your answer. I don't have right now the sensor but i want to ask something else. This "accelerometer" that i described earlier (IMI 603C01) they appear to need some kind of "excitation (IEPE)" but this kind of excitation can only be provided for NI 9234 module but i don't have that module (and that's why i'm using my project with a module NI 9215 screw terminal). Well anyway the question is, do you know if i can only enter the signal in de adapter that i showed you in the picture earlier and then add cables to the screw terminals of the adapter and then conect this ones directly to the screw terminals of the module 9215?. Or do i need some kind of circuit before i enter into the screw terminals of the module ?

[GerdW]

Hi Gerardo,

did you read the manual for your sensor?

On page 2 of the operating guide it explicitely shows how to supply the sensor! It's a so-called ICP device!

Just search for "ICP sensor supply" using your favorite search engine and follow the suggestions/recommendations given…

(Hint/warning: you need a current limiting device! There are cheap solutions like the LM334Z I used for a different acceleration sensor…)

[GerardoGuzman]

Thanks GerdW, i really appreciate your answer. Now i'm trying to make one of this (ICP sensor supply) for my accelerometer and i want to know if you know how to calculate the components or if you have a diagrame to guide me. I don't want to be annoying, rude or lazy is just that i'm not really good at electronics.
I tried something in Proteus and i attached the image for better visualization (It's just a representation). I'm trying to use the one that you told me the "LM334" to mantain constant current of 4 mA and with the 15 ohm resistence that I calculted with the formula given in the datasheet i have 4.5mA  (that it's in the range of the sensor), now i have problems to understand what is the "blocking capacitor" (22 uF) or "decoupling capacitor" and what resistence do i have to put in the "filter resistor" and why is there this resistence.  I attache some other images that have been useful to me for this circuit and i don't know if it's too easy to make or is it  just me that don't understand this circuit. Thanks for everything and i'm going to wait for your answer.

[billko]

How is this even remotely related to LabVIEW?

[GerardoGuzman]

Hi billko. I'm really sorry if i'm asking something out of the area of this forum is just that i have a situation and i can explain this.I'm doing a project about the analysis of vibrations on motors. For what I've been looking for the accelerometers are the best option to achieve this, so the real problem is that i have this components:

1-CompactRIO 9074 system

2-NI 9215, NI 9263, NI 9421 and NI 9472 modules

I want to make the acquisition of the accelerometer data. I don't have the IMI 603C01 accelerometer that National Instrument presents as the best option right now but i have to convince my partners that this sensors are the best way to make the project . Then i noticed that NI 9215 can't read the data from accelerometers without an external ICP sensor supply for the sensor, so i'm trying to understand how to make one of these circuits to show to my partners that we can use this sensor, and then buy this accelerometers and make progress in my project. Thanks for your attention.

[RavensFan]

It sounds like you need to buy some signal conditioning circuits like  http://www.pcb.com/TestMeasurement/Electronics/BatteryPoweredICPSignalConditioners

[GerdW]

Hi Gerardo,

you have shown a snippet from NI9234 spec sheet - here you clearly see it's IEPE capabilities!

Why don't you just use the NI9234?