ABB REX 521 Technical Reference Manual, Standard Configurations page 67

1MRS 751802-MUM Protection Relay
Technical Reference Manual, Standard Configurations
Example of customized interlocking
DC pos. close =
station L/R-switch
in remote
ES pos. open =
Earth switch open
Logic input 1 = SF6 gas alarm
Logic input 2 = Spring not charged
Logic input 3 = Manual stop
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The AND gate becomes an OR function by inverting the digital inputs in the general
digital input settings menu. Thus any of the connected fault signals can disable
closing of the circuit breaker.
&
&
&
REX 521
Interlocking_D
= Close enable
67