Answer / md. jawed akhtar

In open -loop control system, the input has no control over
output variable.
where as in close-loop(or feedback)control system,the input
has control over output variable.In this system,the variable
output is measured and feed to the controller through path(or
loop).In controller compares the desire reference value with
the actual value and acts to reduce the difference between the
two to zero value.

Answer / carl_ellis

An open loop has no feedback, like a timed operation. For
instance, an irrigation system operates for 45 minutes per
day, starting at 10:15 AM. It does this whether the water
is needed or not, because the controller, the timer, has no
feedback about the need for water.

A closed loop uses feedback. In the irrigation example, a
soil moisture sensor provides feedback to a controller to
let the controller make a decision as to whether irrigation
is needed and for how long.

Carl Ellis
Measure First

Answer / sunil.onthekadu77

open loop means
only for indication
but close loop
means suppose
transmitter output
effect the final
controle valve such
as controle
valve,dampers,pumps
etc.

Answer / r_vaya

In close loop has directly control on output , in open loop not possible. 

what step is taken for ESD ( emergency shut down) in DCS REPLY to hashimka20009@gmail.com

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