Despatch P1400+ Temperature Controller - Manual (Page 81)

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Communications Write Enable Type: General Definition
Enables/disables the changing of parameter values via the RS485 communications link, if the
communications option is installed. Possible settings are read only or read/write.
Display code =
CoEn , default setting = r_ W (read/write).
Control Type Type: Controller Parameter
Defines if a controller has one or two control outputs. Single outputs can drive the PV in one
direction only (e.g. heat only, cool only, increase humidity etc). Dual outputs can force the PV to
increase or decrease (e.g heat & cool, humidify and dehumidify etc).
Dual control is not possible on Valve Motor Drive controllers
Display codes =
SnGL and duAL , default value = SnGL .
Also refer to PID , Primary Proportional Band , Process Variable , Secondary Proportional Band
and Valve Motor Control .
Controller Type: Controller Definition
An instrument that can control a Process Variable, using either PID or On-Off control methods.
Alarm outputs are also available that will activate at preset PV values, as are other options such as
PV retransmission and Serial Communications.
Also refer to
Alarm Operation , Indicator , Limit Controller , On-Off Control , PID , Process Variable ,
Retransmit Output and Serial Communications .
CPU Type: General Definition
This stands for Central Processing Unit and refers to the onboard microprocessor that controls all of
the measuring, alarm and control functions of the instrument.
Current Proportioning Control Type: Controller Definition
Current proportioning control can be implemented on units configured with linear current or voltage
output(s). It provides a 4 to 20mA, 0-20mA, 0 to 5V, 0 to 10V or 2 - 10V DC PID output. On-Off
control should not be used with Current proportioning control.
Also refer to
On-Off Control , PID , Primary Proportional Band , Rate , Secondary Proportional
Band and Time Proportional Control .
Cycle Time Type: Controller Definition
For time proportioning outputs, it is used to define time period over which the average on vs. off time
is equal to the required PID output level.
Ct1 , Ct2 and Ct3 are available when option slots 1, 2 or 3
are defined as time proportioning output types. The permitted range of value is 0.5, 1, 2, 4, 8, 16, 32,
64, 128, 256 or 512 seconds. Shorter cycle times will give better control, but at the expense of
reduce life when used with an electromechanical control device (e.g. relays or solenoid valves).
Display codes =
Ct1 , Ct2 and Ct3 , default value = 32.
Also refer to PID and Time Proportioning .
Deadband Type: Controller Parameter
- Refer to Overlap/Deadband .
Derivative Type: Controller Parameter
Refer to Rate .
Deviation Alarm 1 Value Type Type: General Parameter
This is applicable only if Alarm 1 is selected to be Deviation Alarm. A positive value (Deviation High)
sets the alarm point above the current actual setpoint, a negative value (Deviation Low) sets it