4
Table 2.1
PV above Max. Range
PV below Min. Range
Message
Error Type
Cause
Thermocouple / RTD broken
Sensor Open
Under-range
Over-range
CONTROL / ALARM STATUS UNDER PV ERROR CONDITIONS
a) The tuning, if in progress, is aborted.
b) The Profile Cycle, if in progress, enters in HOLD state.
c) Under
Over-range
or
Under-range
error condition, all the control outputs are switched off. However, under
Sensor Open
error, the PID control output power is maintained at the value set for the parameter “Sensor Break Output Power” on
PAGE-12.
d) For Alarm activation, the under-range condition is treated as minimum PV, whereas the over-range and open conditions
are treated as maximum PV. Thus, Process High, positive Deviation Band and Window Band alarms activate under
Over-
range/Open error
. Similarly, Process Low, negative Deviation Band and Window Band alarms activate under
Under-range
error
.
•
MANUAL MODE OPERATION
This operation mode is available only if the control action is PID and if the manual mode operation is permitted at
supervisory level. In this mode, the controller operates in Open loop mode wherein the % Output Power is manually
adjusted by the operator. This mode is often used for process start-up to make sure that the process equilibrium is
achieved before the control is transferred for subsequent automatic (closed loop) control. The controller ensures a
bumpless
Auto / Manual transfer.
The manual mode can be activated or de-activated using ENTER key. While in manual mode, the Upper Readout shows PV
while the Lower Readout shows % Power that can be adjusted using UP/DOWN keys.
Follow the steps below to enter (Activate) into Manual Mode and to revert to (De-activate) Automatic Mode.
1. Hold ENTER key pressed for approximately 2 seconds until front panel indicator M (Manual Mode) turns on.
2.
Release Enter key. The controller is now placed in Manual mode. The Upper Readout displays the PV and the Lower
Readout displays the %Output Power (with the leftmost digit indicating either P (Unidirectional control) or H / C
(Bidirectional control)).
3. Adjust the Output Power using the UP and DOWN keys. Note that in Unidirectional mode, the Output Power is adjustable
between the set Power Low and Power High limits. However, in Bi-directional mode, the Output Power is adjustable from
-100% to +100%.The power range from -100% to 0 is Cool Power (with the leftmost digit indicating C) and 0 to +100% is
Heat Power (with the leftmost digit indicating H).
To de-activate the Manual mode; Hold the ENTER key pressed for approximately 2 seconds until the front panel indicator M
turns off. The controller now enters into Auto control mode with the first power same as that was adjusted last while in Manual
mode.
User Manual
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