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User Manual
Piccolo Range
5.2.4 Control
This selects the control algorithm, which may be PID heat and/or cool or an ON/OFF. The control algorithm may
also be disabled in which case all outputs configured for control will revert to off in the case of a switching output or
0% power demand in the case of an analogue output.
P7
Select P7 to configure Control Type.
Having defined a control type it will be necessary to allocate control outputs using
P11/P12/P13/P14.
None
HP
CP
HP.CP
Ho.CP
Ho
Co
HP.CO
Ho.Co
Control action disabled
PID heating
(default)
PID cooling
PID heat + PID cool
ON/OFF heat + PID
cool
ON/OFF heating
ON/OFF cooling
PID heat + ON/OFF
cool
ON/OFF heat +
ON/OFF cool
The control function block is configured for PID (three
term) heating, no cooling. Typical applications include
furnaces and ovens.
The control function block is configured for PID (three
term) cooling, no heating. May be used in cryogenic
applications.
The control function block is configured for PID (three
term) heating and PID cooling. Typical applications
include extruder temperature control.
The control function block is configured for ON/OFF
heating and PID (three term) cooling.
The control function block is configured for ON/OFF
heating, no cooling. Simple heat only applications.
The control function block is configured for ON/OFF
cooling, no heating. Simple cool only applications
The control function block is configured for PID (three
term) heating and ON/OFF cooling. Typical
applications include extruder temperature control.
The control function block is configured for ON/OFF
heating and cooling. Simple heat/ cool applications.
Control options are described
in section 7.1
P8
Select P8 to configure Non Linear Cooling Type.
P8 is only shown if the control type, P7, is heat and cool.
The cooling type algorithm matches the controller to the characteristics of the cooling
medium. It is typically used in the control of extruder barrel temperatures where the
cooling medium may be water, oil or forced air.
Lin Linear (default) The characterisation of the cool output is linear
oiL Oil
The cooling output is pulsed. Being non-evaporative,
oil cooling is pulsed in a linear manner. It is deep and
more direct and will not need such a high cool gain as
fan cooling.
H2o
FAn
Water
Forced air (Fan)
The cooling output is pulsed. A complication with
water-cooling comes if the zone is running well above
100°C.
Usually the first few pulses of water will flash off into
steam giving a greatly increased cooling capacity due
to the latent heat of evaporation.
When the zone settles down, less or even no
evaporation is a possibility and the cooling is less
severe.
To handle evaporative cooling, water cool mode would
generally be chosen.
This technique delivers much shortened pulses of
water for the first few percent of the cooling range,
when the water is likely to be flashing off into steam.
This compensates for the transition out of the initial
strong evaporative cooling.
This is much gentler than water cooling and not so
immediate or decisive because of the long heat
transfer path through the finned aluminium cooler and
barrel.
With fan cooling, a cool gain setting of 3 upwards
would be typical and delivery of pulses to the blower
would be linear, i.e. the on time would increase
proportionally with percentage cool demand
determined by the controller.
This is typically used for
extruder applications and is
described further in section
7.1.6 ‘Cooling Algorithm’.
46 Part No HA031260 Issue 1 May -12