pmg511en21p01 23
5.6.3.1 Setting the Proportional Band for Heating
[PAR2 → H-P]
and Cooling
[PAR2 → C-P]
If the Process Value
(PV)
is within the proportional band
(P)
, the ON / OFF ratio must be adjusted during
the proportional period
(T)
. The defined proportional control
(time proportional control)
section is called the
proportional band. Default value: 10.0. It is set in
°C / °F /
%.
5.6.3.2 Setting Integral Time for Heating
[PAR2 → H-I]
and Cooling
[PAR2 → C-I]
MV
s from integrative and proportional operation become identical if the deviation is consistent. The time required
for the two
MV
s to match is called the integral time. Default value: 0 s.
Note: Integration does not occur if the integral time is set to 0. Setting the integral time too short can increase correction
movements and cause control oscillations.
5.6.3.3 Setting Derivative Time for Heating
[PAR2 → H-D]
and Cooling
[PAR2 → C-D]
According to the difference of the ramp, the
MV
obtained from the derivative operation and the time required to
reach the
MV
obtained from the proportional control are called the derivative time.
Note: The differentiation member stops when the derivative time is set to 0.
5.6.3.4 Setting Control Period for Heating
[PAR3 → H-T]
and Cooling
[PAR3 → C-T]
If a relay or SSR is used with control proportional to the
MV
output, the output will be on for a period of time
(within
the control period, as a percentage of the MV)
and will remain off for the rest of the time. The preset period when
the output is ON / OFF is called the proportional control period.
Control with SSR drive output is faster than relay output. Therefore, setting a shorter control period can achieve
more sensitive temperature control.
Default – Relay: 20.0 s / SSR: 2.0 s.
Note: If heating and cooling control is used, configure the control period for heating and cooling separately.
5.6.3.5 Offset Correction / Manual Reset Settings
[PAR2 → REST]
When selecting the P / PD control mode, there are some temperature differences even after the
PV
is stable
because the temperature rise and fall times of the heater are inconsistent with the thermal characteristics of the
controlled section, such as heat capacity and heater capacity. This temperature difference is called
OFFSET
. The
offset can be corrected by manual reset.
Default: 50%
Manual reset settings based on control results:
Under stable control conditions, set the offset to 50% if
PV
and
SV
are the same, above 50.0% if
PV
is lower than
SV, and below 50.0% if
PV
is higher than SV.
Note: offset correction can only be used if proportional control (P) is on. If the integral value is set to 0, the manual reset
parameter is displayed. The user cannot configure the manual reset setting during heating and cooling control. Instead,
the setting is automatically set to 0% for heating and cooling. Only applicable if the integration time is set to 0 during P
or PD control. Switching from heating and cooling control to normal control (P, PD control) automatically sets the reset
settings to 50%
Set reset under 50!
Offset
Offset
Set reset over 50!
ON_Offset