AUBER INSTRUMENTS
WWW.AUBERINS.COM
2020.06
P5/10
PV
SV
SV-Hy
100
97
Relay On
When heating,
If PV
(SV-Hy), relay on
If PV
(SV+Hy), relay off
(SV=100, Hy=3)
Figure 5. On/off control mode.
SV+Hy
103
3) Auto-tune
In most cases the fuzzy logic enhanced PID control is very adaptive and may
work well without changing the initial PID parameters. If not, users may need to
use auto-tune function to let the controller determine the parameters
automatically. If the auto tuning results are not satisfactory, you can manually
fine-tune the PID constants for improved performance. Or you can try to modify
the initial PID values and perform auto tune again. Sometimes the controller will
get the better parameters.
Before auto-tune, please make sure this controller is wired correctly.
Temperature sensor, relay, heater are connected to the controller correctly. Also
confirm your hysteresis band Hy is set to a small number such as 0.5 (default
value). The auto-tune can be started by setting parameter At = 1, then auto-tune
will start automatically. In this ramp/soak controller, user can start the auto-tune
any time when a program is running, on hold, or stopped. When auto-tune is
running, the lower wind
ow will flash between “At” and the current set temperature.
During auto tuning, the instrument executes on/off control at the current set
temperature. After 2-3 times on/off action, the microprocessor in the instrument
will analyze the period, amplitude, waveform of the oscillation generated by the
on/off control, and calculate the optimal value for the P, I, and D.
When auto-
tune is finished, the lower window will stop flashing “At”; only the set
temperature will be shown in the lower window. Controller will resume running
the program. Generally, you will only need to perform auto tuning once. After the
auto tuning is finished, controller will set parameter “At” to
0 automatically.
To manually stop auto-tuning, please set AT to 0.
For this controller, the auto-tune should not be activated when the controller is
ramping because the result obtained at one temperature is optimized for that
temperature only. The auto-tune should be activated at the most critical
temperature where you need to hold the temperature in tight precision. User
should program a long soak step for the critical temperature and only activate
the auto-tune after the process temperature has reached the set temperature.
For example, if 500˚F is the most import temperature you need to hold in tight,
set r01 = 2000, t01 = 30, C01 = 500, r02 = 0, t02 = 0, C02 = 0. When temperature
reaches 500˚F, set AT =
1 to activate the auto-tune. When auto-tuning is finished,
set th
e steps back to the original program. The PID parameters obtained at 500˚F
may works fine at temperatures higher than 500˚F (but it may be a little slow).
But these parameters may not work well at lower temperature range.
5.3.4.
Cycle time “t”
It is the time period (in seconds) that the controller uses to calculate its output.
The default cycle time is 10 seconds. For example, when t = 20, if the controller
decides output should be 10%, the heater will be on 2 second and off 18 seconds
for every 20 seconds. To drive external relay or contactor output, it should be set
longer to prevent contacts from wearing out too soon. Normally 20~40 seconds.
5.3.5.
Input digital filter “FIL
t
”
If measurement input fluctuates due to noise, then a digital filter can be used to
smooth the input. “FILt” may be configured in the range of 0 to 50. Stronger
filtering increases the stability of the readout display, but causes more delay in
the response to change in temperature. FILt = 0 disables the filter. Default FILT
is set to 20.
5.3.6.
Hysteresis b
and “Hy”
The Hysteresis Band parameter Hy is also referred as Dead Band or Differential.
It permits protection of the on/off control from high switching frequency caused
by process input fluctuation. Hysteresis Band parameter is used for on/off control
and auto-tune.
Please note that the cycle time can also affect the action. If the temperature
passes the Hy set point right after the start of a cycle, the controller will not
respond to the Hy set point until the next cycle. If cycle time is set to 20 seconds,
the action can be delay as long as 20 seconds. Users can reduce the cycle time
to avoid the delay.
5.3.7.
Decimal point setting “dP”
dP is used to define temperature display resolution.
When dP = 0, temperature display resolution is 1° (C or F).
When dP = 1, temperature display resolution is 0.1° (C or F). The temperature
will be displayed at the resolution of 0.1° for input below 1000° (C or F), and 1°
for input over 1000° (C or F).
5.3.8.
Output range limits
“OUTL” and “OUTH”
OUTL and OUTH allow you set the output range low and high limit.
OUTL is a useful feature for a system that needs to have a minimum amount of
power as long as the controller is powered. For example, if OUTL = 20, the
controller will maintain a minimum of 20% power output even when input sensor
failed.
OUTH can be used when you have an overpowered heater to control a small
subject. For example, if you set the OUTH = 50, the 5000 Watts heater will be
used as 2500W heater (50%) even when the PID wants to send 100% output.
5.3.9.
Configuration Privilege “Lock”
To prevent the parameters and the program being changed accidently, you can
completely or partially lock the parameters and the program after the initial setup.
The configuration privilege is d
etermined by “lock”. It can be set to any value
between 0 and 50.
The factory default setting for lock is 0, which means all parameters are unlocked.
It allows all parameters and program steps being viewed and edited during
operation.
When Lock is set to any other value from 1 to 50, all the parameters are locked
and cannot be edited.
Note
: In any situation that parameters that are locked, you can always view and
change the “lock” value after you view all field parameters. Change the value will
immediately change the privilege level.
5.3.10.
Input selection code for
“
Sn
”
Please see Table 4 for the acceptable sensor type and its range.
Table 4. Code for Sn and its range.
Sn
code
Sn
Value
Input device
Display range
(° C)
Display range
(° F)
K
3
K (thermocouple)
-30 ~ +1300
-22 ~ +2372
E
4
E (thermocouple)
-30 ~ +700
-22 ~ +1292
J
5
J (thermocouple)
-30 ~ +900
-22 ~ +1652
T
6
T (thermocouple)
-199.9 ~ +400
-328 ~ +752
S
7
S (thermocouple)
-30 ~ +1600
-22 ~ +2912
R
8
R (thermocouple)
-30 ~ +1700
-22 ~ +3092
CU50
0
Cu50 (RTD)
-50 ~ +150
-58 ~ +302
PT1
1
Pt100 (RTD)
-199.9 ~ +200.0
-328 ~ +392
PT2
2
Pt100 (RTD)
-199.9 ~ +600.0
-328 ~ +1112
