Appendix H. Glossary - GE Masoneilan SVI II ESD Installation And Maintenance Manual

Smart valve interface with sil3 emergency shutdown pst controller

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Appendix H. Glossary

Accuracy

Actuator Type

Algorithm

ATC Air to Close

ATO Air to Open

CALIBrate

In a control valve position is measured between mechanical motion limits in the

valve. These limits can include position variations due to actuator and valve

rigidity. therefore, accuracy is referenced to positions within normal valve travel,

independent of rigidity effects at mechanical limits stops. Accuracy is the great-

est deviation from the expected position within the normal travel, expressed as

normal travel percentage.

An actuator is a device that transforms an input signal (mainly an electrical sig-

nal) into motion. A HART

rent signal and causes an actuation function. There are many types of HART

actuators; a positioner is a type of actuator. A device of type Actuator can not be

connected to a circuit intended for a device of type Transmitter.

An algorithm is a procedure or formula for solving a problem. There are several

algorithms entailed in SVI II ESD operation. SVI II ESD has a position control algo-

rithm that is a modified PID algorithm. Other embedded algorithms in SVI II ESD

include STOPS method for calibrating stroke, and autoTUNE method for estab-

lishing the best parameters for the PID algorithm.

The combination of a single acting actuator and control valve where the valve is

closed when air pressure is applied to the actuator.

The combination of a single acting actuator and control valve where the valve is

open when air pressure is applied to the actuator.

A positioner mode of operation in which you have access to changing stroke cal-

ibration, input signal, and tuning parameters.

compliant actuator receives a 4 - 20 mA control cur-

Masoneilan SVI II ESD Installation and Maintenance Manual

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