32
Useful
Functions
Handling
T
: De
viation (
˚
C)
T: Time
n05 = 7.0
(Initial value)
0
Small
Large
n05: Response coefficient
[Note]
1.
When starting auto-tuning, make sure that
the oil temperature is nearly equal to the room temperature (in stable condition)
.
Leave the main machine under no load (stopped).
2.
If
the remote signal turns OFF
or
an alarm is activated
during execution of auto-tuning, an error occurs (auto-tuning cannot be
executed), and the corresponding error message appears.
To cancel the error, press the key. (The unit returns to the normal mode.)
Check the remote signal, or examine the cause of the alarm. After taking a corrective action, execute auto-tuning again.
3.
Before starting auto-tuning, select an operation mode to determine the control target thermistor. (Select any operation mode other
than “9”.)
Operation mode 0, 3 or 4
Tank liquid temperature thermistor
Then, set Parameter [n04] by referring to [Note]
4.
below.
4.
In Step 2, the machine may be over-cooled. To suppress machine over-cooling, specify an auto-tuning end condition in Parameter
[n04].
Parameter [n04] Outlet oil temperature decrease (Auto-tuning end condition)
Setting range: 0.0 to 10.0˚C, Initial value: 8.0˚C
When the tank liquid temperature has decreased by the temperature specified with this parameter, auto-tuning (data collection) ends.
If the specified temperature range is too small, temperature control gain may not be correctly calculated. You should set this
parameter to the maximum value in the range where it does not cause damage to the machine.
5.
To calculate more suitable temperature control gain based on the data collected in Step 3, you must specify a response coefficient
in Parameter [n05]. (Through response coefficient adjustment, you can select whether to place importance on stability or response
speed.)
Parameter [n05] P and I gain calculation coefficient (Response coefficient)
Setting range: 0.1 to 10.0, Initial value: 7.0
Setting a smaller value improves stability. Setting a larger value improves response speed.
If the set value is extremely large or small, the unit may not normally perform temperature control. First, you should execute
auto-tuning with the initial value of 7.0.
6.
Depending on the condition of the control target (machine), the unit may not calculate suitable temperature control gain in a single
auto-tuning operation. You should
execute auto-tuning two or three times to average the calculated values
, or
use the value
that most frequently appears (except for an extreme value)
.
To calculate a more suitable temperature control gain, you may change Parameter [n05] (see [Note]
5.
above).
7.
In the following cases, temperature control is not stabilized because the compressor turns ON/OFF without being subjected to
inverter control.
(1) Operation under small load (Cooling capacity: 30% or less)
(2) Rapid load change (Transition period)
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