Response Electronics CL6011B Specifiche Scaricare il pdf (Pagina 132)

4Ć50 FST Configuration

Original Ć June 1990CE4.2:CL6211

CASC CASC

INSTRUCTION NAME: CASC (cascade)

DESCRIPTION: This instruction provides cascade control linkage between two direct control

points, the second of which must have remote set point mode. The implied value position (IVP) of

the primary loop is automatically placed into the set point of the secondary loop when the

secondary loop is in the remote set point mode.

When the secondary loop is in the manual mode, the IVP of the primary loop tracks the process

variable of the secondary loop, if the primary loop is not in manual mode.

When the secondary loop is in the local automatic mode, the IVP of the primary loop tracks the local

set point of the secondary loop, if the primary loop is not in manual mode.

When the secondary loop is in the remote set point mode, the IVP of the primary loop becomes the

percent of span remote set point for the secondary control loop.

The primary loop will perform normal PID control action when the secondary loop is in the remote

set point mode as long as IVP of the secondary loop is not output limited. When the secondary

controller IVP is output limited, and the change in IVP of the primary control loop causes the

secondary loop to drive harder against its output limit, the integral action is disabled in the primary

loop. This prevents the primary loop from winding up its output when the secondary loop is already

output limited in the direction the primary loop is tending to drive it. The following guidelines apply

to the use of the cascade function:

H The primary loop must be set up for increase to open valves.

H The secondary loop must have the auto/manual/RSP station type.

H The cascade function cannot be used in the same loop as the TRK or OVRD functions.

H The secondary loop can use any of the PCA modifier functions.

H CASC can be used only once per direct control point.

CONFIGURATION FORMAT: CASC (

Loop tag >>

Track overrides manual enable>>

Comment >>

(Continued on next page)

1 2 ... 127 128 129 130 131 132 133 134 135 136 137 ... 319 320

Nessun commento

Response Electronics CL6011B Specifiche Pagina 132