89
Manual Mode Enable
Type: Controller Parameter
Determines whether operator selection and de-selec-
tion of manual control is enabled. If the mode is en-
abled in Set-Up mode, pressing the AM key in Opera-
tor Mode will normally activate or deactivate manual
control mode. However, disabling PoEn in whilst man-
ual control mode is active will lock the controller into
Manual Mode and pressing the MAN/AUTO key will no
longer cause a return to PID (automatic) control. To exit
from Manual Mode, PoEn must temporarily be re-en-
abled to allow PID control to be re-established. PoEn
can then be safely disabled.
It is possible to use a controller as a permanent “Manu-
al Station” by disabling PoEn to deliberately lock it into
Manual Mode.
Manual Mode can also be selected using a digital input
if one has been fitted and configured for this function.
When in Manual Mode, the MANUAL LED indicator
flashes.
Display code = PoEn, default setting = diSA
Also refer to Manual Mode and PID
Master & Slave
Type: Controller Denition
The terms master & slave are used to describe the con-
trollers in applications where one instrument controls
the setpoint of another. The master controller can trans-
mit the setpoint to the slave using an analog DC linear
signal. The slave controller must have a matching a re-
mote setpoint input. Some Profile Controllers can trans-
mit their setpoint via serial communications serial com-
munications. For this method, the Profiler must be able
to act as a communications master device and the slave
must have a compatible communications option fitted.
Also refer to Cascade Control, Retransmit Output, Re-
mote Setpoint, Serial Communications, Setpoint
Minimum Motor On Time
Type: VMD Controller Parameter
This defines the minimum drive effort needed to initiate
valve movement, if the valve was previously stationary.
This parameter is used primarily to ensure that valve
frictional and inertial effects do not cause controller
drive to be ignored by the valve.
If Self-Tune is OFF, this parameter can be used to influ-
ence valve activity. Larger values reduce valve activity
but increase the risk of the process oscillating. Self-
Tune monitors on-control valve activity and will mini-
mize it automatically.
Too large a value of Minimum Motor On Time can im-
pair the effectiveness of the Self-Tune facility; if pro-
cess variable oscillations persist whilst Self-Tune is
running, it may be for this reason
Display code = tr, default setting = 1.00
Also refer to Motor Travel Time, Self-Tune and Valve
Motor Drive Control.
Modulating Valve
Type: VMD Controller Denition
A valve that can be positioned anywhere between fully
closed and fully open by means of an incorporated mo-
tor. A typical application would be controlling tempera-
ture in a furnace heated by gas burners. A Valve Motor
Drive (VMD) Controller is used to move the valve to the
desired position in order to control the gas valve. Some
modulating valve motors require linear (mA or VDC)
signals to position the valve. These require standard
Process Controllers (using PI control) instead of VMD
types.
Also refer to Motor Travel Time, PI Control and Valve
Motor Drive Control.
Motor Travel Time
Type: VMD Controller Parameter
The Motor Travel Time parameter is the time the valve
takes to travel from one physical end stop to the other.
This parameter is used by the Valve Motor Drive con-
trol algorithm when calculating how long to energize
the “Valve Open” or “Valve Close” outputs to bring the
process on to control.
It is important that this time accurately reflects the
time taken to travel between the physical limits oth-
erwise control will be impaired. The motor travel time
should be stated in the valve specification or can ob-
tained from the supplier or manufacturer. Failing that,
the valve should be timed from the fully closed to fully
opened position. The controller can be placed in Man-
ual Mode to assist with the timing of valve movement.
Display code = ton, default setting = 1.00.
Also refer to Manual Mode Enable, Minimum Motor On
Time and Valve Motor Drive Control.
Multi-Point Scaling Enable
Type: Indicator Parameter
When an Indicators Multi-Point Scaling function is en-
abled by setting MPS to EnAb in Configuration Mode,
up to 9 breakpoints can be defined to linearize the in-
put signal. This only applies to mA, mV or Voltage in-
put types. For each breakpoint, an input scale value
is entered, followed by the value to be shown at the
breakpoint.
Display code = MPS, default setting = diSA
Also refer to Indicator, Multipoint Scaling Set Up and
Process Variable.
Multi-Point Scaling Set Up
Type: Indicator Parameter
For each breakpoint, the input scale value (ScAn) is
entered as a percentage of the input span, followed by
the value to be shown (diSn) in display units, for this
input value.
Each breakpoint’s input scale value must be higher
than the previous value, but the display values can be
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