Question { Adani, 34475 }

Hi,
I'd like to know the purpose of MOS (maintenance override
switch). At site, these switches are installed in a
stanchion with the transmitter (connected to ESD). thank
you.

Answer

maintenance override function is used for bypassing shutdown
processing so that it is not executed by safety logic during
partial maintenance such as specific input.Creating bypass
logic using a dedicated override allows the (HIS) to safely
perform maintenance override for SCS (system control station)
However Maintenance override can not executed from the HIS
unless this switch is in the permission status.

Question { Marafiq, 8199 }

difference between DCS @ SCADA system?
and how can use in field

Answer

DCS : Distributed Control System , to control and monitor process over  plant or a defined limited Area , platforms

SCADA : Supervisory Controlled and Data Acquisition  is a a pecific I/O's  but distributed over a distant , like pipeline thru dessert ,...etc