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29/08/2018 A: SENTHILKUMAR VELAYUTHAM, PETRORABIGH KSA, sugasen@gmail.com
In more practical way -PRD mode MH lock will not be obey by the controller and flow exceeds to obey the master SV ,Many of the IOP flow situation CASCADE Mode will be released to Manual but in PRD it will maintain same as PRD, flow transmitter failure situation also PRD will help
26/03/2010 A: Balasubramanian Iyer, Nexen CNOOC Limited, balasubramanian.n@aol.in
To my knowledge to explain PRD mode in automatic process control in simple way: In Normal Cascade Controller the Master sends the error signal in the form of PV to the Slave and tries to Zero in the difference ie the error. In Case of the PRD the Master sends signal to the Slave in the form of MV value to the Slave.
31/01/2010 A: omsakhti kesavan, GFPC, sakthikesavan@gmail.com
PRD mode is primary direct mode. This mode help to bypass secondary loop in cascade control mode system and thereby sends commands to direct final control element as received from master controller. This mode can be seen in Yokagawa make DCS.
17/11/2009 A: Prabhat Choudhary , IOCL, prabhatchoudhary26@gmail.com
PRD mode is generally referred for Primary direct mode. This mode help to bypass secondary loop in cascade control mode system and thereby sends commands to direct final control element as received from master controller. This mode can be seen in Yokagawa make DCS.
16/11/2009 A: keith bowers, B and B Consulting, kebowers47@gmail.com
Proportional--Reset Rate(integral)---Derivative