Emerson 20/20 User Manual

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Vission 20/20 • Operation and Service Manual •Vilter/Emerson • 35391SC 1.8.5153
Section 9 • Compressor Scheduling
Overview
This menu allows the operator to schedule control set-
point switching during the day and week. This feature 
can be enabled and disabled from the Compressor 
Schedule screen. Up to four setpoint “switch” events 
can be scheduled per day, see Figure 9-1. Compressor 
Scheduling Screen.
Scheduling Setpoint
Schedule:
•  The options for selection are “Enable” & “Disable”. 
The operator is allowed to confi gure setpoints relat-
ed to schedule events, but only when the schedule is 
disabled.
• The operator can Enable Compressor Scheduling 
Feature, only if Time Intervals are in order of Event 1 
< Event 2 < Event 3 < Event 4 for all days. If events are 
not in order, invalid events are marked with caution 
symbol to indicate the operator to correct events and 
then enable feature.
Control Mode:
•  These drop-down boxes allow selection of operat-
ing modes which gets switched once schedule event 
time is achieved.
•  The list of allowable modes depends on the number 
of controllers selected in the confi guration screen. 
For example, if the number of Suction Pressure 
Control Setpoints selected is “2” and the number 
of Process Temperature Control Setpoints selected 
is “1”, then Control Mode drop-down box will have 
“Unscheduled”, “Suction Pressure SP1”, “Suction 
Pressure SP2” and “Process Temperature SP1” as op-
tions for selection. 
•  If Control Mode is selected as “Unscheduled” and 
Time set in an event is achieved, then control mode 
will not get switched. Hence Control Mode can be set 
Figure 9-1. Compressor Scheduling Screen