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NPIX-4DI4DO keep inputs galvanically isolated? - Printable Version

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+--- Thread: NPIX-4DI4DO keep inputs galvanically isolated? (/Thread-NPIX-4DI4DO-keep-inputs-galvanically-isolated)

NPIX-4DI4DO keep inputs galvanically isolated? - EUROKEY - January-9th-2020


we would like to connect 4 different external signals to the input ports of the 4DI4DO module while we need to keep the netPI galvanically isolated against the input ports andalso the input ports need to stay galvanically isolated to each other input port.

This is not possible with the 4DI4DO module, right?
The module itself requires 24V DC so we need one 24DC power for the netPI and another galvanically isolated one for the 4DI4DO module. But each input port is connected together and with the power source for the 4DI4DO module.

But we are able to connect one external signal which will then stay galvanically isolated to the netPI if the both power sources are. Right?

We need to connect really expensive hardware and must ensure that a mayor fault will not harm the other systems.
Thanks for the clarification.


RE: NPIX-4DI4DO keep inputs galvanically isolated? - Armin@netPI - January-9th-2020

Hello Manuel,

your understanding is absolutely right.

With the DIO module the intension was

 a.) not to load the netPI's internal power supply with additional power/current needed on the DO side
 b.) galvanic isolation of the DI's and DO's

This is why we decided to shift the "load problem" to the module itself by giving the user the option to power it with any power supply he wants

And yes, in best case you have two power supplies, one for netPI and one for the DOs with no common GND to keep netPI isolated.