ADM2483 Isolation circuit

Using Arduino General Electronics
1

Dear all

I have used ADM2483 RS485 trans receiver for end application.Since we know ADM2483 need 2 ground. in my design . i have designed my transformer with 12V 1A gnd1 output & 5V 500mA GND2 output.

i have test setup where i am giving 12V battery backup.12V of the battery and GND1 made common.

Further 12V/GND1 is converted into 5V/GND1 which is used primary side of the ADM2483

5V/GND2 of the transformer output given to secondary of ADM2483

With aux and standby connected i could able to communicate with multiple devices

Now assume my Auxiliary supply fail and standby circuit alone running
In this case ADM2483 only gets primary voltage and ground but not 5v and GND2 at secondary side.

In order to achieve this how should i design my hardware. Communication should work when auxiliary fail and stanby present.

Is there any recommended circuit from Experts here. I have attached my schematic for reference,

QVI2O.jpg
QVI2O.jpg1494×601 58.2 KB

QVI2O.jpg
QVI2O.jpg1494×601 58.2 KB

2

Do you need the isolation barrier? If not you should use a standard RS485 transceiver as its much
simpler.

If you need to have isolation you will need both supplies isolated from each other and both active for
it to work as they are entirely separate circuits.