©2025 Copeland LP.
026-1803 R13 Supervisor I&O User Guide 9 - 25
Schedule Priority
The schedule used is based on the following priority scheme
and within the following categories.
• Maintenance Schedule - If any of the maintenance schedules
are active, (in the Master Schedule) that maintenance schedule
is used as the current schedule. Time until next change of state
and time since previous change of state will be given in
minutes.
• Holiday/Special Schedule - The DAY SCHED input provides
which day of the week or holiday schedule to follow. When DAY
SCHED input indicates that a holiday is active, all schedules
follow the selected holiday schedule. If a holiday is entered and
a schedule does not have the selected special daily schedule
defined, then it reverts back and use the regular schedule for
that day of the week.
• Standard Weekly Schedule - If a daily schedule is not defined for
a day of the week then the control algorithm searches back in
time for the last defined state change. If no daily schedules are
defined, the output of the schedule is set to Off.
Overlapping Events
The user is allowed to enter overlapping events, however, the
first ON event and first OFF event of out-of-sequence events is
picked up.
Operation When Not Within Programmed Date
Range
If the current system date does not fall into any of the date
ranges specified, the schedule control loop is considered not
active. A special value (NO_VALUE) is written to the output,
and TUCOS is set to a maximum TUCOS value (2 days or
2880 minutes) while TSCOS still reflects the actual elapsed
time since last change of state.
The Master Schedule
If a daily schedule is not defined for a day of the week, the
control algorithm searches back in time for the last defined
state change. If no daily schedules are defined, the output of
the schedule is set to OFF. The DAY SCHED input provides
which day of the week or holiday schedule to follow. When
DAY SCHED input indicates that a holiday is active, all
schedules follow the selected holiday schedule. If a holiday is
entered and a schedule does not have the selected special
daily schedule defined, then it reverts back and uses the
regular schedule for that day of the week.
If any of the maintenance schedules are activated, that
maintenance time schedule shall be used as the current
schedule. Time until next change of state and time since
previous change of state will be given in minutes. During
bypass, override, or demand control, TUCOS output is set to
maximum TUCOS value and TSCOS reflects the actual time
since change of state.
9.14.8 Control Override
When the EMERGENCY input is active, the normal control
algorithm is overridden and CONTROL OUT is immediately
forced to the value specified by the EMERGENCY OUT
parameter.
Slave Schedule
The ON/OFF times of the schedules (except for maintenance
schedules) can either be absolute or relative. When the times
are relative to the corresponding Master events, positive time
represents how much time after the Master event and
negative time represents how much time ahead of the Master
event. There is at most one relative time for either ON time or
OFF time for a single day.
The following illustrates the Master Schedule DAY SCHED
Output with the Slave schedule behavior:
• Maintenance Schedule - follow the Master's
maintenance schedule. Normal day of week schedules
are ignored even if they are active.
• Holiday Schedule/Normal Day of Week - if
Maintenance Schedule is active, run a Maintenance
Schedule. A relative event time of the corresponding
schedule is used to modify the master's schedule while
the absolute event times take precedence over the
Master’s events.
• Bypass, Override, or Demand Shed active
(TUCOS=MAX_TUCOS) - events with negative relative
times start immediately. If the delay (as indicated by
positive relative time of Slave's event) is longer than the
duration of the Master’s special event, the Slave does not
react to that Master's special event.
9.14.9 Control Bypass
When the BYPASS TO ON input is active, the control output is
forced to the ON state regardless of normal schedules.
Likewise, when BYPASS TO OFF is active, control is forced to
the OFF state. BYPASS TO ON has the higher priority over
BYPASS TO OFF.
9.14.10 Control Override
When the EMERGENCY input is active, the normal control
algorithm is overridden and CONTROL OUT is immediately
forced to the value specified by the
EMERGENCY OUT parameter.
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