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11 Timer Feature
11.1 Timer Feature
The timer feature is only available on the Standard
model. It consists of a Delay Timer and an On Timer.
When the Timer Enable parameter is set to Disabled
the timer will not be used and the delayed start time
and on time are ignored. Note: If the setpoint has been
set to ramp, this will still be active, even if the timer is
Disabled.
When Enabled the timer will take control of the Set-
point as defined by the Delayed Start Time and On
Time parameters. Enabling the timer has no effect until
the controller is power cycled or the control is disabled
then re-enabled.
11.2 Delay, Ramp & Timer Diagram
The delay, ramp and soak is only available on the stan-
dard model.
1. From power-up, if control is in the enabled state, or
whenever control is changed from disabled to en-
abled, the unit delays process control (i.e. control is
still disabled) until the Delay Timer expires (time as
set by Delayed Start Time). If this is OFF, step 1 is
omitted.
2. Setpoint ramps from the current PV to the target
setpoint at Ramp Rate (‘RAMP’ alternating with the
current effective SP value indicates it is still ramp-
ing). If Ramp Rate is OFF the effective setpoint
steps directly to target setpoint.
3. After any Delay and/or Ramp completes, the set-
point ‘Dwells’ at the target value while the On-Timer
counts down (time set by On Time).
4. When the On Timer finishes the control switches off
(i.e. control is disabled). If the On Timer has been
set to OFF, step 4 is omitted, and control is main-
tained at the setpoint indefinitely.
The timer, control power down state and the power-up action have the following relationship:
Control state
at power down
Power-up
Action
setting
Timer Enable
parameter
setting
Delayed
Start Value Control state at power-up
Enabled Last Disabled N/A Control Enabled
Disabled Last Disabled N/A Control Disabled
Enabled On Disabled N/A Control Enabled
Disabled On Disabled N/A Control Enabled
Enabled Last Enabled Off Control Enabled
Disabled Last Enabled Off Control Disabled
Enabled On Enabled Off Control Enabled
Disabled On Enabled Off Control Enabled
Enabled Last Enabled Time Set Control Disabled until Delay timer expires
Disabled Last Enabled Time Set Control Disabled
Enabled On Enabled Time Set Control Disabled until Delay timer expires
Disabled On Enabled Time Set Control Disabled until Delay timer expires
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