SC 2043 noise problem

[Flexrob]

I post again my question, since as a comment nobody saw it.
I analyzed more in deep the problem. These area the results: the high frequency noise is due to brushless power supply.
However strain gauges are connected to the SC 2043 with a shielded cable. Unexpectedly is just the shield ground connection that carries into the acquisition board this noise. In fact, with all the cables disconnected from SC 2043, with the exception of the shield terminals (connected to pin 1 and 2, i.e. AIGND pins), I measure exactly the same noise.

How is it possible? Where should I connect the cable shield to avoid this problem?


Thanks,
regards


Luca Bascetta

[RIO-Todd]

I'm assuming that you are using the brushless power supply as an external power supply for the SC-2043. When connecting an external power supply to the SC-2043 you should connect the external power to the +5 and GND pins on the J8 terminal of the SC-2043. You should not connect the ground of an external power supply to the AIGND pins of the data acquisition device.

Page 2-3 in the SC-2043 user manual goes over how to connect an external power supply to the SC-2043. The manual is linked below. I hope this helps.

SC-2043-SG User Manual
http://digital.ni.com/manuals.nsf/webAdvsearch/0F043CE8C54F479A8625665E0063587F?OpenDocument

Todd D.
Applications Engineer
National Instruments

[Flexrob]

Absolutely not. The brushless power supply is used only for the motors but it creates electromagnetic noise.
This noise is caught by the shield of the strain gauge cable.

Luca Bascetta