does scc sg04 have low pass filter?

[myo]

Hi.. I am using SCC-SG04 for full bridge strain gauge with SC2345. I found the voltage output on oscilloscope with much noises when I directly measured from SCB 68 output which linked with SC2345.

High frequency noises was reduced a lot when I used simple passive RC low pass filter circuit. (cutoff freq is 1kHz) But there are still noises. Voltage excitation 2.5V and gauge resistor values are 120 ohms.

Therefore, I wish that is there any filter in SCC SG04? I found that  manual described it has 1.6kHz LP filter. Actually I am not sure what my cutoff freq should be and I think there should be less noise if SCC SG04 has LP filter. Am I right?

I would like to use DAQ in PC and I don't know which suitable hardware to use. I already have Labview 8.

Please reply me.

Thanks.

Myo

[Neal M]

Hello myo,

First off, welcome to the NI forum.  To answer your question, yes there is a 1.6kHz RC low pass filter on the SCC-SG04 module.  I am unsure why you are getting noise when you measure the signal directly, however there are several possibilities.  The most likely of which is since the device is not attached to a DAQ card (as it usually is), there may be some grounding issues, the device may not be powered correctly, or some other issue related to connecting the devices together.

The type of DAQ cards we usually reccomend for use with the SC 2345 are our E series or M series cards. You can use the SCC Advisor to help you choose as well. If you already have some HW, just choose what you have; It will be included in a quote, but you can use the advisor to see which HW works with the rest of your setup.  Some of these cards have hardware filters as well, and you may be able to do some filtering in software.

If you are looking to purchase a DAQ card for your computer, I suggest calling or emailing our sales department, especially if you want more information about the different cards we offer.

[myo]

HI Neal M.

Thanks alot for your reply. I think grounding issue might give me a lot of noises.The links are quite useful. I will contact the sale dept. for more info sooner or later.

Thank you again.

Myo