www.pulsar.pl           EN54M                                  RED POWER plus 
 
 
5.2.  Input of collective failure: EXTi. 
The EXT IN (external input) technical input indicating collective failure is intended for additional, external  
devices that generate the failure signal. Disconnection of the EXTi terminals will cause a failure of the PSU and 
generate a failure signal at the ALARM output. 
The  EXTi technical input  is  not  galvanically isolated  from  the  power  supply. The "minus"  terminal is 
connected to the power supply. 
The connection of external devices to the EXT IN input is shown in the electrical diagram below. Relay 
outputs or "open collector" signal outputs can be used as the signal source. 
 
 
 
Fig. 8. Connections to the EXTi input. 
 
The EXTi input has been adjusted to work with EN54C-LB4 and EN54C-LB8 fuse modules generating a 
failure  signal  in  case  of  a  fuse  fault  in  any  of  output  sections  (see  section  5.6.1).  To  guarantee  a  correct 
cooperation between the fuse module and the EXTi input, the connections shall be made as presented in the 
diagram below. 
 
 
 
Fig. 9. Example of a connection with the fuse module EN54C-LB8.