Is there an analog voltage input module to capture 0-20mV with BNC connector, that will fit in the NI cDAQ-9178 8-slot USB Chassis?

[miblab]

Trying to capture data from a load cell by Omega (LC202-1K) with output specs of 2mV/V that works with 10 VDC supply, hence need to capture a 0-20mV range.

Currently I have a NI cDAQ 9178 USB 8-slot chassis and a NI-9215 analog input module with BNC connector. Its voltage input range is +/-10V. I am wondering if this will be accurate enough in the 0-20mV range. If not, is there a different analog input module I can use which will be more accurate in the 0-20mV range and has BNC connector.

Thank you for your help

Best

[Marcus_M]

Hello Miblab,

The current module that you have, the NI-9215, has a voltage accuracy of .003V on the +-10V range.  This module most likely isn't accurate enough for your application since the error could be over 10% of your reading. 

How many channels would you like for your new module to have?  Is there a certain resolution you are looking for?  

Regards,

Marcus 

[miblab]

Hi Marcus,

Yes. I think I will need to amplify the signal from the load cell before connecting it to the NI-9215 module. For this I am planning to add a signal conditioner module by Omega DMD-465. However, if there is a more sensitive module by NI that you know then I could see if that will work.

I already have a NI-9215 module with 4 channels and need to use only 1 channel to collect the voltage from the load cell. The accuracy can be the same 3mV in the +/- 10V range. The Omega DMD-465 module will allow me to amplify the signal up to 15 V , however, I will probably use it in its default setting that will amplify it up to approximately 5V.

Just out of curiosity, does NI have analog input modules with BNC connecters that have much greater accuracy than the NI-9215. If yes, then I might be willing to swap the NI-9215 modules that I have (5 in total).

Thanks much

MibLab

[Marcus_M]

Hi MibLab,

Amplifying the signal to a larger amplitude would allow for a better reading.  If your signal was on the scale of 5V the accuracy of the card would be as precise as .06% of your signal.  This is one possibility.  

A second possibility would be to use the NI-9205, http://sine.ni.com/nips/cds/view/p/lang/en/nid/208800  

This module, although it doesn't have BNC terminals, has a minimum voltage range of 200 millivolts, and a minimum voltage range accuracy of 157 microvolts.  

Please let me know if there is anything else I can do to help you find the appropriate module.

Regards,

Marcus