Emerson 20/20 service manual Compressor Scheduling, Scheduling Setpoint

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 configure 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 configuration 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

Vission 20/20 • Operation and Service Manual •Vilter/Emerson • 35391SC 1.8.5153 9 – 1