Transmitter Failure Mode Low or High

R

Thread Starter

Rico

Transmitters have an independent circuit which is designed to provide backup alarm output if the microprocessor hardware or sofware fails. The alarm level is user-selectable using the failure mode switch (output is driven either High or Low). My question is, what's the advantage of selecting 'Low' or 'High', does it matter either way? Is it advisable to drive the output to 'Low' say 3.75 mA, i.e. is low power means fail safe?
 
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The transmitter fail mode is determined by process it is monitoring. If the transmitter in question fails one way or the other, what is the more conservative control system response as far as safety, equipment protection, revenue etc.

Greg Ponto
Lead Combustion Turbine Specialist
Elwood Operations
(815) 423-9883 x2232
Email: [email protected]
 
The transmitter fail mode is determined by process it is monitoring. If the transmitter in question fails one way or the other, what is the more conservative control system response as far as safety, equipment protection, revenue etc.

Greg Ponto
Lead Combustion Turbine Specialist
Elwood Operations
(815) 423-9883 x2232
Email: [email protected]
i have situation when transmitter become iop after overshoot level more than 106.25%, and control valve in DCS become manual from Auto control. And it effect to process boiler feed water due to control valve maintain in manual control mode. Any suggestion to prevent this control turn to manual after iop. DCS : centum VP yokogawa.
 
i have situation when transmitter become iop after overshoot level more than 106.25%, and control valve in DCS become manual from Auto control. And it effect to process boiler feed water due to control valve maintain in manual control mode. Any suggestion to prevent this control turn to manual after iop. DCS : centum VP yokogawa.
What is iop??
 
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