zape
Full Member level 2
I have a desing whith the following componets:
1) National Instruments daq board, with two DAC outputs, 4 pseudo-differential inputs and 8 digital IOs.
2) An isolated power supply(+5V, +-15V).
3) A board with an amplifier.
3) The equipment under test (EUT).
The power supply feeds the amplifier board and the EUT. The common of the power supply is not connected to earth (chassis).
The problem I see is as follows. The DAQ board connects in the PCB the digital ground(DGND), the analog output ground (AOGND) and the analog input ground (AIGND) to a common point and this point is connected to earth.
So if the power supply feeds the EUT and I am cabling its digital outputs (with a DGND line) to the DAQ board, if I connect one of the analog outputs and its reference AOGND to the amplifier board, I will have a ground loop.
To break the ground loop I am thinking in using a small signal transformer. Does anyone could recommend me any manufacturer or any other solution? I have heard about common chockes in this kind of applications, but I honestly do not know.
Any advice will be appreciated.
1) National Instruments daq board, with two DAC outputs, 4 pseudo-differential inputs and 8 digital IOs.
2) An isolated power supply(+5V, +-15V).
3) A board with an amplifier.
3) The equipment under test (EUT).
The power supply feeds the amplifier board and the EUT. The common of the power supply is not connected to earth (chassis).
The problem I see is as follows. The DAQ board connects in the PCB the digital ground(DGND), the analog output ground (AOGND) and the analog input ground (AIGND) to a common point and this point is connected to earth.
So if the power supply feeds the EUT and I am cabling its digital outputs (with a DGND line) to the DAQ board, if I connect one of the analog outputs and its reference AOGND to the amplifier board, I will have a ground loop.
To break the ground loop I am thinking in using a small signal transformer. Does anyone could recommend me any manufacturer or any other solution? I have heard about common chockes in this kind of applications, but I honestly do not know.
Any advice will be appreciated.