Usually analog I/O need 24V DC power. If you PLC has internal 230VAC~24VDC converter. Then your question will be how to make 230VDC redundant. Nomally 2 different 230AC income power cannot be connected together. While some UPS support parrelling configuration. If you PLC don't have internal converter. You can arrange 2 230VAC~24VDC supply and a power voting unit or diode to balance the 24V power come from different 24V power module.