Response Electronics CL6011B Especificaciones descargar pdf (Pagina 37)

3Ć17 Theory of Operation: Point Processing

Original Ć June 1990 CE4.2:CL6211

calculations. (The configuration engineer can take advantage of this

SVD output signal to initialize or balance any FST computations that are

being performed in place of the standard PCA computations.)

The standard PCA functions such as SP limiting, SP velocity limiting, SP

tracking, etc. are all supported by the Control Sequence PCA types when

the CONTROL FST function block is executed.

3.3.1.9.3 Equations for STATION FST Function Block

The Signal Value Analog (SVA) input to the STATION FST function block

for a Control Sequence PCA type must be a percent value equal to the

valve position (current signal) to be sent to the final control element,

exclusive of any Bias that is present on the loop. The equations for the

STATION FST function block are:

SVA(out) = SVA(in) + Bias + Transfer Bias

for an increase open valve:

IVP = SVA(out)

for an increase close valve:

IVP = 100% - SVA(out)

The Signal Value Discrete (SVD) output of the CONTROL FST function

block is set equal to the state of the deviation alarm (Alarm A).

The standard STATION functions such as IVP limiting, output tracking,

Mode limiting, alarming, Transfer Bias ramping, Bias balancing (when

Transfer Bias ramping is disabled), and Watch Dog Timer for DDC or

Supervisory modes are all supported by the Control Sequence PCA

types when the STATION FST function block is executed.

3.3.2 Station Types

The station type of a direct control point is defined by the modes that are

valid for it (e.g., an Automatic/Manual station type). Several

combinations of station types are valid, and are defined as follows: MAN,

AUT/MAN, AUT/MAN/RSP, AUT/MAN/SUP, AUT/MAN/DDC, MAN/DDC,

AUT/MAN/DDC/SUP.

The mode of operation for a direct control point primarily determines who

can adjust the set point and IVP. The different modes that are available

are: Manual (MAN), Automatic (AUT), Remote Set Point (RSP),

Supervisory (SUP), and Direct Digital Control (DDC). The mode of a

point can be changed by an FST or an operator at a PROVOX console or

operator station.

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Response Electronics CL6011B Especificaciones Pagina 37