Ascon Tecnologic - KX5P Line - ENGINEERING MANUAL - PAG. 15
• In multi loop machinery where the fast method reduces
the calculation error due to the effect of the other loops.
3.
The
EvoTune
type is suitable when:
• You have no information about your process;
• You can not be sure about the end user skills;
• You desire an auto tune calculation independently
from the starting conditions (e.g. set point change
during tune execution, etc).
Note:
Fast auto-tune can start only when the measured
value (PV) is lower than (SP + 1/2SP).
Available:
When [56] cont = PID
Range:
-4... 8 where:
-4 Oscillating auto-tune with automatic restart at
all set point change;
-3 Oscillating auto-tune with manual start;
-2 Oscillating auto-tune with automatic start at the
first power up only;
-1 Oscillating auto-tune with automatic restart at
every power up;
0 Not used;
1 Fast auto tuning with automatic restart at every
power up;
2 Fast auto-tune with automatic start at the first
power up only;
3 FAST auto-tune with manual start;
4 FAST auto-tune with automatic restart at all set
point change.
5 EvoTune with automatic restart at every power up;
6 EvoTune with automatic start at the first power
up only;
7 EvoTune with manual start;
8 EvoTune with automatic restart at all set point
change.
Note:
All auto-tunes are inhibited during program execution.
[58] tunE - Manual start of the auto-tune
Available:
When [56] cont = PID.
Range:
oFF
The instrument is not performing the auto-tune;
on
The instrument is performing the auto-tune.
[59] HSEt - Hysteresis of the ON/OFF control
Available:
When [56] cont is different from PID.
Range:
0... 9999 engineering units.
[60] Pb - Proportional band
Available:
When [56] cont = PID.
Range:
1... 9999 engineering units.
Note:
Auto-tune functions calculate this value.
[61] ti - Integral time
Available:
When [56] cont = PID.
Range:
OFF
Integral action excluded;
1... 9999 seconds;
inF
Integral action excluded.
Note:
Auto-tune functions calculate this value.
[62] td - Derivative time
Available:
When [56] cont = PID.
Range:
oFF - derivative action excluded;
1... 9999 seconds.
Note:
Auto-tune functions calculate this value.
[63] Fuoc - Fuzzy overshoot control
This parameter reduces the overshoot usually present at
instrument start up or after a set point change and it will be
active only in this two cases.
Setting a value between 0.00 and 1.00 it is possible to slow
down the instrument action during set point approach.
Setting
Fuoc = 1
this function is disabled.
PV
SP
time
2
1
3
Available:
When [56] cont = PID
Range:
0... 2.00.
Note:
Fast auto-tune calculates the Fuoc parameter while
the oscillating one sets it equal to 0.5.
[64] tcH - Cycle time of the heating output
Available:
When at least one output is programmed in order
to be the heating output (H.rEG), [56] cont = PID
Range:
1.0... 130.0 seconds.
[65] rcG - Power ratio between heating and cooling
action
(relative cooling gain)
The instrument uses the same PID parameter set for heat
and for cool action but the efficiency of the two actions is
usually different.
This parameter allows to define the ratio between the efficien-
cy of the heating system and the efficiency of the cooling one.
An example will help us to explain the philosophy.
Consider one loop of a plastic extruder. The working tem-
perature is equal to 250°C.
When you want to increase the temperature from 250 to
270°C (
D
T = 20°C) using 100% of the heating power (resis-
tor), you will need 60 seconds.
On the contrary, when you want to decrease the temperature
from 250 to 230°C (
D
T = 20°C) using 100% of the cooling
power (fan), you will need 20 seconds only.
In our example the ratio is equal to 60/20 = 3 ([65] rcG = 3)
and it say that the efficiency of the cooling system is 3 time
more efficient of the heating one.
Available:
When two control actions are programmed
(H.rEG and c.rEG) and [55] cont = PID.
Range:
0.01... 99.99.
Note:
Auto-tune functions calculate this value.
[66] tcc - Cycle time of the cooling output
Available:
When at least one output is programmed in order
to be the cooling output (c.rEG), [56] cont = PID.
Range:
1.0... 130.0 seconds.
[67] rS - Manual reset (integral pre-load)
It allows to drastically reduce the undershoot due to a
hot restart. When your process is steady, the instrument
operates with a steady power output (e.g.: 30%).
If a short power down occurs, the process restarts with a
process variable close to the set point while the instrument
starts with an integral action equal to zero.
Setting a manual reset equal to the average power output (in our
example 30%) the instrument will start with a power output equal
to the value it will use at steady state (instead of zero) and the
undershoot will become very little (in theory equal to zero).
Available:
When [56] cont = PID.
Range:
-100.0... +100.0%.