Figure 91. Auto Cascade Operation
Master Controller
Remote slave
setpoint tracks
master output.
Local setpoint on
Master.
Slave Controller
Section 8 Operation Examples
Cascade Operation in Auto
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•
The slave setpoint tracks (automatically remains equal to) the slave process
variable while in manual. This feature eliminates the need for the slave to
respond immediately to any deviation when the mode is changed from manual
to auto (cascade). Without setpoint tracking, the response to any deviation
would be to ramp the slave output at the reset rate.
•
The output of the master tracks the setpoint of the slave while the slave is in
manual. This ensures that the local (slave) setpoint and remote setpoint (master
output) are in balance prior to placing the slave loop in cascade (auto) mode.
•
The setpoint of the master tracks the master process variable while the slave is
in manual. This causes the setpoint of the master to vary indirectly in response
to manual output changes in the slave loop. When the system is switched to
auto, the master setpoint switches from track to local, and there is no process
upset because the track function eliminates any deviation in the master loop.
•
Since the control element is directly manipulated by the slave, the master is
Summary of Contents for Ability 800xA Series
Page 1: ...Power and productivity for a better worldTM 800xA for MOD 300 Operation System Version 6 0 ...
Page 2: ......
Page 3: ...800xA for MOD 300 Operation System Version 6 0 ...
Page 14: ...Table of Contents 14 3BUR002418 600 A ...
Page 74: ...Area Graphic Display Section 3 CCF Displays 74 3BUR002418 600 A ...
Page 102: ...Batch Connectivity to M0D 300 Section 4 TCL Displays 102 3BUR002418 600 A ...
Page 120: ...TLL Messages Section 5 TLL Displays 120 3BUR002418 600 A ...
Page 212: ...Viewing Abnormal State on MOD Loop Displays Section 8 Operation Examples 212 3BUR002418 600 A ...
Page 320: ...BRKPTS Appendix A Runtime Templates 320 3BUR002418 600 A ...
Page 322: ...Updates in Revision Index A 322 3BUR002418 600 A ...
Page 330: ...Index 330 3BUR002418 600 A ...
Page 331: ......