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Regarding Galvanic isolation in 4-8 channel Analog input measurement.

Question asked by PrateekJain-28889 on Dec 20, 2013
Latest reply on Jan 8, 2014 by PrateekJain-28889

Hello,

Recently i designed an 8-channel Fully universal analog input module (T/C,RTD,4-20mA,0-10VDC). I referred some of your reference circuits. The supply to my module is 24VDC. I have isolated and regulated it using isolated DC-DC converter (Mornsun Part) to +-12V.power output feeds Only power is isolated , my CPU (ADuC834) and analog section are non-isolated. Inputs are differential. If user powers my module with 24V bus and with the same bus he powers a 2-Wire or 4-wire Transmitter. Then the negative of 24V bus is somehow electrically connected to system gnd( CPU and analog section gnd). So i guess the purpose of galvanic power isolation gets defeated. What care should i take and what could be the adverse effects of not taking care.

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