Voting unit requirement
If we have two redundant power supply comming from UPS , connected to two different power supply unit (SD834) , what is the requirement of voting units.
Will it increase the system redundcany or any protection will be provided.
Hi, only one Voting unit SS822 is needed. +24V,GND from both power supplies are connected at input of the Voting unit. Output +24V and GND from Voting unit is connected to power input of CPU, IO cards. The aim of 2 power supplies and Voting unit is to keep the control system powered even during plant shutdowns. It is increasing availability of the control system.
Connection of +24V between Voting unit and control system shoud be without fuse or circuit breaker. Circuit breakers shall be installed between power supplies and Voting unit.