PPI Zenex Pro, User Manual

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User Manual Zenex Pro
Parameter Description
Settings
Default Value
POWER-FAIL RECOVERY METHOD
Abort
The timer operation is suspended until a new start command is
issued.
Start
The timer re-runs the complete soak time.
Continue
The Soak Timer resumes operation for the balance time.
(Default : Continue)
Continue
(Re)Start
Abort
SOAK TIMER OPERATION
Figure 8.1
SP
PV
Time
PV
Set Time
Timer count down starts
PV enters start band,
Start Band
Basic Operation
The Soak Timer is essentially a preset timer that can be configured to run as :
(a) A Free Running Timer by setting timer ‘Start Band’ to 0. That is, the timer starts counting down immediately upon issuance
of Start Command by the user and continues until set time is elapsed.
(b) A Setpoint Dependent Timer. That is, after issuance of Start Command, the count down starts only after the PV reaches
within timer ‘Start Band’. The timer start band is a symmetrical band centered around the SP. For example, for a start band
of 2°C and SP value of 100°C, the count down begins once the PV reaches a value within 98°C (SP - Start Band) to102°C
(SP + Start Band). Note that, once the PV enters ‘Start Band’, the timer continues to run regardless of whether the PV
remains within or outside the ‘Start Band’.
Hold Band Operation
The timer is also provided with a ‘Hold Band’ that can be enabled to make sure that the timer counts down only while the PV is
within the ‘Hold Band’. That is, the timer pauses (holds counting down) whenever the PV is outside the ‘Hold Band’. The ‘Hold
Band’ is set with respect to the SP and can be set above or below or above and below the SP. For example, a 5 °C Hold Band
below the SP (say,100°C) will force the timer in pause state whenever the PV is equal or less than 95 ° C (SP - Hold Band).