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MCT-CM
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5.5 Control Loops (Single Set point Operation)
The loop view screens provide direct viewing options for the control and monitoring of the MCT control loops
and process monitor inputs. The loop screens allow the user to adjust the current loop set points (SP) and view
the process variables (PV) and percentages of output (%) for each loop. If the loop is a process monitor input
only, the set point and percentage of output will not be displayed since no control is associated with the input.
NOTE: The OEM configuration of MCT may allow the operator to change the loop set point, activate manual
mode and initiate an auto tune at the loop control itself. If any of these permissions are active, any
change made at the loop control will be indicated on the loop view screens. If these permissions are
not enabled, any change made at the loop control will be overridden by the setting from MCT
If in doubt about which permissions, if any, are allowed from the loop control, contact the equipment
manufacturer or consult the OEM configuration. Any changes made at the loop controls are not
logged or protected by MCT security settings. These changes will not appear in the audit trail. If
adjustments to control loop settings are to be made only by authorized users with the proper security
access, the loop permissions should be disabled in the MCT configuration or other means are
necessary to prevent unauthorized users from accessing the loop controls.
5.5.1 Loop View
The Loop screen is accessed from the home “View” menu. The number of loops shown can be from one to
five depending upon the sett
ing made for “Number of Loops to View” on the Navigation screen under the Setup
menu.
The
left and right arrow buttons will be displayed if the number of loops and monitors configured in the system
exceeds the number shown on the screen. They will allow the user to cycle through each loop and monitor
point available in the system. When the first or last loop is reached, MCT will automatically wrap around to the
beginning or end of the list to show the next loop.
The
set point entry field is the area where the screen can be touched in order to bring up the keypad entry
window. Using the numeric entry keypad, a new set point can be entered. Once entered, the new set point will
be shown in the set point entry field. Adjustment of the set point is locked out if an automated ramp/soak
program is running unless the program is first placed into Hold.
The
percent output entry field is the area where the screen can be touched in order to bring up the keypad
entry window. Using the numeric keypad, a new fixed percentage of output can be set for the loop. In order to
be able to enter a fixed output percentage, the loop must first be placed in manual output mode. This is done
by pressing the “%” tag on the screen.
Set Point Entry
Field
Loop Units
Loop Name
Press PV value
for historical
min/max.
Press PV tag to
reset historical
min/max.
Press % tag to
enable/disable
manual output.
Percent Output
Entry Field