How to connect SMOKE DETECTOR SENSOR with KC868-A64?

[jigneshk5]

I don't know how to define different i2c bus, I can't find in the library documentation: https://github.com/xreef/PCF8575_library
I'm defining i2c bus for (relay1-16) like this PCF8575 pcf8575_out(0x24,15,4);
and I'm defining i2c bus for (DI1-16) like this PCF8575 pcf8575_in(0x24,15,4);

Is the 15,4 value need to be changed, what change is needed in the definition. Please help.

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Don't you think i2c bus could be same for the relay and digital input pins as I did that definition of INPUT and OUTPUT in setup function:
for(int i=0;i<16;i++)
{
pcf8575_in.pinMode(i,INPUT);
}
pcf8575_in.begin();

for(int i=0;i<16;i++)
{
pcf8575_out.pinMode(i,OUTPUT);
}
pcf8575_out.begin();