IM 05D01D02-03E (2)
2. Lists of Parameters
■
Operating Parameters
Parameter
Symbol
Name of Parameter
Setting Range and Description
Initial Value
User Setting
Target Item
in CD-ROM
Alarm 1-setpoint
Alarm 2-setpoint
Alarm 3-setpoint
PV alarm / SP alarm: -100.0 to 100.0% of PV
input range
Deviation alarm: -100.0 to 100.0% of PV input
range span
Output alarm: -5.0 to 105.0%
An alarm common to the 1.SP to 4.SP parameters.
PV high limit/SP high limit alarm:
100.0% of PV input range
Deviation alarm: 0.0% of PV
input range span
Other PV/SP low limit alarm:
0.0% of PV input range
Output high limit alarm: 100.0%
Output low limit alarm: 0.0%
Auto-tuning
OFF: No auto-tuning
1: Auto-tuning for 1.SP 2: Auto-tuning for 2.SP
3: Auto-tuning for 3.SP 4: Auto-tuning for 4.SP
AUTO: Performs auto-tuning to all groups 1 to 4.
OFF
Target setpoint
number selection
0: Uses target setpoint via communication
1: Selects target setpoint 1 (1.SP).
2: Selects target setpoint 2 (2.SP).
3: Selects target setpoint 3 (3.SP).
4: Selects target setpoint 4 (4.SP).
1
PID parameter display
number
MENU: Move to FL parameter display
1Gr to 4Gr: Display of each PID
parameter
MENU
PV input filter
OFF, 1 to 120 second.
Used when the PV input fluctuates.
OFF
PV input bias
-100.0% to 100.0% of PV input
range span
Used to correct the PV input range.
0.0% of PV input range
span
Setpoint ramp-up-rate
Setpoint ramp-down-
rate
OFF
0.0% + 1 digit of PV input range span
to 100.0% of PV input range span
Set ramp-up-rate or ramp-down-rate
per hour or minute.
Sets unit in ramp-rate-time unit (TMU).
OFF
OFF
1.0% of PV input range
span
ON/OFF rate detection
band
ON/OFF rate high limit
ON/OFF rate low limit
0.0 to 100.0% of PV input range span
ORL + 1 digit to 105.0%
100.0%
-5.0% to ORH - 1 digit
0.0%
Target setpoint-1
Target setpoint-2
Target setpoint-3
Target setpoint-4
0.0 to 100.0% of PV input range
However, between target setpoint limiter
lower limit (SPL) and upper limit (SPH).
0.0% of PV input range
LL communication
interface selection
(A1)
(A2)
(A3)
(AT)
(SP.NO)
(PID)
(FL)
(BS)
(UPR)
(DNR)
(ORB)
(ORH)
(ORL)
(1.SP)
(2.SP)
(3.SP)
(4.SP)
OFF: Communication is carried out via the
RS485 communication terminals.
ON: Communication is carried out via the light-loader
adapter.
with communication : OFF
without communication : ON
—
—
—
—
—
Ref.2.1(5)
Ref.2.1(6)
Ref.4.1(1)
Ref.1.1(1)
—
—
Ref.2.1(1)
Ref.3.3(5)
Ref.3.3(4)
Ref.4.1(1)
Heater burnout current
measurement 2
(HC2)
The current value of the
heater burnout detector
is shown on the display of
the HC1 or HC2 parameter.
Heater burnout current
measurement 1
These are not setpoints.
(HC1)
Heater burnout current
setpoint 2
(HB2)
OFF
When PCMD = 6 or 7 :
PCCH = 100.0%,
PCCL = 0.0 %
When PCMD = 8 or 9 :
PCCH and PCCL = 1.0 %
Heater burnout current
setpoint 1
Low limit for
PV color change
High limit for
PV color change
OFF, or 1 to 50 A
When PCMD (PV color mode parameter) = 6 or 7 :
-100.0 to 100.0 % of PV input range
When PCMD (PV color mode parameter) = 8 or 9 :
-100.0 to 100.0 % of PV input range span
(HB1)
ON/OFF rate
This is not a setpoint.
The moving average (for 5
cycle times) of the control
output is shown.
(OR)
Output high limit
Heating-side output high limit
(in heating/cooling control)
Output low limit
Cooling-side output high limit
(in heating/cooling control)
-5.0 to 105.0%
Heating-side limiter in heating/cooling
control: 0.0 to 105.0% (OL < OH)
-5.0 to 105.0%
Cooling-side limiter in heating/cooling control: 0.0 to
105.0% (OL < OH)
100%
Heating/cooling control:
100.0%
0.0%
Heating/cooling control:
100.0%
ON/OFF control hysteresis
Heating-side/cooling-side
ON/OFF control hysteresis
(in heating/cooling control)
In ON/OFF control: 0.0 to 100.0% of PV input
range span
In heating/cooling control: 0.0 to 10.0%
ON/OFF control: 0.5% of PV
input range span
Heating/cooling control: 0.5%
(OH)
(OL)
(H)
Direct/reverse action
switching
0: reverse action, 1: direct action
0
(DR)
(PCCH)
(PCCL)
(LL)
“Super” function
(SC)
Deviation
(PV-SP)
+
-
Direct
action
Reverse
action
Control output
0%
100%
Ref.4.1(4)
Ref.2.1(3)
OFF
OFF: Disable
1: Overshoot suppressing function
Suppresses overshoots generated by abrupt changes
in the target setpoint or by disturbances.
2: Hunting suppressing function (Stable mode)
Suitable to stabilize the state of control when the load
varies greatly, or the target setpoint is changed.
Enables to answer the wider characteristic changes
compared with Response mode.
3: Hunting suppressing function (Response mode)
Enables quick follow-up and short converging time of
PV for the changed target setpoint.
Note: Use “SUPER” function (SC) 2 or 3 in PID control or PI control.
“SUPER” function 2 or 3 is not available in the following control:
1) ON/OFF control
2) P control (control for proportional band only)
3) PD control (control for proportional band and derivative item only)
4) Heating/cooling control
Do not use hunting suppressing function when control processes
with response such as flow or pressure control.
●
PID-related Parameters
The following parameters are displayed when “1Gr” is set to PID parameter display number (PID). In this case, the corresponding target setpoint is 1.SP
(target setpoint-1).
To set PID corresponding to target setpoint 2 to 4, set “2Gr”, “3Gr”, or “4Gr” to PID. The relevant parameters will then be displayed.
Parameter
Symbol
Name of Parameter
Setting Range and Description
Initial Value
Proportional band/Heating-
side proportional band
(in heating/cooling control)
0.1 to 999.9%
In heating/cooling control: 0.0 to 999.9%
(heating-side ON/OFF control applies when 0.0)
5.0%
Integral time
Heating-side integral time
(in heating/cooling control)
OFF, 1 to 6000 second
OFF, 1 to 6000 second
240 second
60 second
Derivative time
Heating-side derivative time
(in heating/cooling control)
Manual reset
-5.0 to 105.0%
(enabled when integral time “1.I” is OFF)
The manual reset value equals the output value
when PV = SP is true.
For example, if the manual reset value is 50%,
the output value is 50% when PV = SP
becomes true.
50.0%
User Setting
Target Item
in CD-ROM
(1.P)
(1.I)
(1.D)
(1.MR)
Cooling-side integral
time
OFF, 1 to 6000 second
240 second
(1.Ic)
Cooling-side
proportional band
0.0 to 999.9%
(Cooling-side ON/OFF control applies
when 0.0)
5.0%
(1.Pc)
Ref.4.1(1)
*
Parameters relating to PV or setpoints should all be set in real numbers.
For example, use temperature values to define target setpoints and
alarm setpoints for temperature input.
*
The “User Setting” column in the table below is provided for the customer to record setpoints.
*
The “Target Item in CD-ROM” column in the table below provides references from User’s Manual (Reference) (CD-ROM
Version) which describes items in more detail and items that are not contained in this manual.
60 second
Ref.4.1(1)
OFF, 1 to 6000 second
Cooling-side derivative
time
Deadband
-100.0 to 50.0%
In heating/cooling control, a reagion where
both of the heating- and cooling-side outputs
are presented, or none of them is presented,
can be set.
3.0%
(1.Dc)
(1.DB)
Zone PID reference
point-1
100% value of
PV input range
(1.RP)
0.0 to 100.0% of PV input range.
Note that 1.RP
ⱕ
2.RP.
Refer to the table below for recording setpoints when two sets or more of PID parameters are used.
Parameter
n=2
n=3
n=4
n.P
n.I
n.D
n.MR
n.Pc
n.Ic
n.Dc
n.DB
None
None
n.RP
Reference deviation
OFF, 0.0 to100.0% of PV input range span
Used to select PID constants according to a deviation from
the setpoint. The 4th group of PID constants is used when
the controller fails to keep track of the deviation.
OFF
Ref.4.1(1)
(RDV)
■
Auto-tuning
Auto-tuning is a function with which the controller
automatically measures the process characteristics
to automatically set the optimum PID constants. This
function does not work when the controller is per-
forming on-off control. The UT351/UT321 employ
the “Limit Cycle Method.” As shown in the figure
on the right, the controller temporarily changes its
control output in a step-waveform manner. Then, it
calculates the optimum proportional band (P), inte-
gral time (I) and derivative time (D) from the result-
ing response to set them in their respective param-
eters. If the Output High Limit (OH) and Output Low Limit (OL) parameters are already configured, the control output turns on and off only
between the output’s high and low limits during auto-tuning.
●
Auto-tuning Using Zone PID (see “
■
PID Switching (Zone PID)” later in this manual)
Setting of
AT Parameter
Auto-tuned Setpoint
OFF
-
Auto-tuning is turned off (disabled).
1
Determines the values of 1.P, 1.I and 1.D parameters by auto-tuning.
2
Determines the values of 2.P, 2.I and 2.D parameters by auto-tuning.
3
Determines the values of 3.P, 3.I and 3.D parameters by auto-tuning.
4
The setpoints when auto-
tuning is started
Determines the values of 4.P, 4.I and 4.D parameters by auto-tuning.
AUTO
Median value of each zone
width
Determines the values of all PID parameters in use by auto-tuning.
Remarks
The AT parameter settings numbered 1 to 4 in the table above are dependent on how many zones have been set. For example, if you have set
two zones, you can use AT parameter settings 1 and 2. Likewise, if you have set three zones, you can use AT parameter settings 1, 2 and 3.
■
Hysteresis (for Target Setpoints (On-Off Control) and Alarm Setpoints)
Hysteresis can be set in on-off control setpoints and alarm setpoints as well. With the hysteresis settings, it is possible to prevent relays from
chattering.
●
When hysteresis is set in a target setpoint
●
When hysteresis is set in an alarm setpoint
PV value
Point of on-off action
(Target setpoint)
Hysteresis
Output
On
Off
Output
On
Off
PV value
Point of on-off action
(Alarm setpoint)
Hysteresis
Example of hysteresis set in PV high limit alarm
■
Target Setpoint Ramp Setting Function
Use this function to prevent the target setpoint from changing suddenly. The ramp setting function works when:
[1] the target setpoint is changed (example: change in “1.SP” from 100
°
C to 150
°
C);
[2] the target setpoint number is switched (example: switch from “1.SP” to “3.SP”);
[3] the power is turned on or the controller is recovered from power failure;
[4] a change is made from manual operation to automatic operation; or
[5] a change is made from the STOP state to the RUN state.
If the target setpoint before switching is smaller than the target setpoint
after switching, the controller operates according to the settings of the
Setpoint Ramp UP (UPR) and Ramp Time Unit (TMU) parameters. If the
target setpoint before switching is greater than the target setpoint after switch-
ing, the controller operates according to the settings of the Setpoint Ramp
Down (DNR) and Ramp Time Unit (TMU) parameters. The figure on the
right shows an example when the Target Setpoint Number (SP.NO) param-
eter is switched. The 1.SP and 2.SP parameters are set to 500
°
C and 640
°
C,
respectively. Thus, there is a temperature difference of 140
°
C between the
1.SP and 2.SP parameters. This example shows how the temperature is
changed by as much as this temperature difference over a period of two minutes. In this
example, the UPR parameter is 70
°
C and the TMU parameter is 1 minute.
■
PID Switching (Zone PID)
Using a zone PID, you can automatically switch between groups of PID constants according to the temperature zone. You can set a maximum
of three temperature zones.
Setting Method:
[1] Set the Zone PID Selection (ZON) parameter to
“ON”.
[2] Define a reference point.
When using two zones, define only reference point 1
(1.RP) between the minimum and maximum values of
the PV input range.
When using three zones, define reference points 1 and
2 (1.RP and 2.RP) in the same way as noted above.
Note: Set the maximum and minimum values, as close as possible to those of the actual range to be controlled, in the Maximum Value of PV Input Range
(RH) and Minimum Value of PV Input Range (RL) parameters. Otherwise, the controller may fail to determine the optimum values when auto-
tuning is carried out.
■
Setup Parameters
●
Control Function-related Parameters
Alarm-1 type
1
1
Alarm-2 type
2
Alarm-3 type
1
Alarm-1 hysteresis
Alarm-2 hysteresis
Alarm-3 hysteresis
Alarm-1 delay timer
Alarm-2 delay timer
Alarm-3 delay timer
0.0 to 100.0% of PV input range span
Output alarm: 0.0 to 100.0%
0.5% of PV
input range span
Output alarm:
0.5%
An alarm is output when the delay timer expires after the
alarm setpoint is reached.
0.00 to 99.59 (min, sec.) (enabled when alarm-1 type
AL1 is 1 to 20 or 28 to 31)
0.00 to 99.59 (min, sec.) (enabled when alarm-2 type
AL2 is 1 to 20 or 28 to 31)
0.00 to 99.59 (min, sec.) (enabled when alarm-3 type
AL3 is 1 to 20 or 28 to 31)
0.00
(AL1)
(AL2)
(AL3)
(HY1)
(HY2)
(HY3)
(DY1)
(DY2)
(DY3)
Target setpoint
limiter upper limit
Target setpoint
limiter lower limit
PV color mode
100.0% of
PV input range
Ref.3.3(4)
Ref.3.3(2)
Ref.3.3(4)
Ref.2.1(8)
Ref.2.1(2)
Ref.4.1(2)
Ref.2.1(4)
Ref.4.1(4)
communi-
cation
function
0.0% of
PV input range
0.0 to 100.0% of PV input range where, SPL < SPH
Places a limit on the range within which the target
setpoint is changed.
(SPH)
(SPL)
(PCMD)
Control output cycle time
Heating-side control output cycle
time (in heating/cooling control)
Cooling-side control
output cycle time
1 to 1000 second
30 second
1 to 1000 second
30 second
(CT)
(CTc)
Preset output/Heating-side
preset output
(in heating/cooling control)
Cooling-side preset
output
-5.0 to 105.0%
In heating/cooling control: Heating side 0.0 to 105.0%
In Stop mode, fixed control output can be generated.
0.0%
0.0 to 105.0%
In Stop mode, cooling-side fixed control output can be
generated.
0.0%
(PO)
(POc)
PID control mode
0: Standard PID control (with output bump at SP change)
1: Fixed point control (without output bump at SP change)
Choose fixed point control when controlling pressure or flow rate.
0
Zone PID selection
OFF: SP selection
ON: Zone PID
ON
(C.MD)
Ramp-rate time unit
setting
0: hour, 1: minute
Time unit of setpoint ramp-up (UPR) and setpoint
ramp-down (DNR)
0
(TMU)
Protocol selection
0
Baud rate
0: 600, 1: 1200, 2: 2400, 3: 4800, 4: 9600 (bps)
4
Parity 0:
None
1: Even
2: Odd
1
Stop bit
1, 2
1
Data length
7, 8: Fixed at 7, when the P.SL parameter is set to MODBUS (ASCII).
Fixed at 8, when the P.SL parameter is set to MODBUS (RTU)
or Ladder Communication.
8
Address
1 to 99
However, the maximum number of stations connectable
is 31.
1
Minimum response
time
0 to 10 (
⫻
10 ms)
0
0: PC link communication
1: PC link communication (with sum check)
2: Ladder communication
3: Coordinated master station
4: Coordinated slave station
7: MODBUS (ASCII)
8: MODBUS (RTU)
10: Coordinated slave station (loop-1 mode)
11: Coordinated slave station (loop-2 mode)
(P.SL)
(BPS)
(PRI)
(STP)
(DLN)
(ADR)
(RP.T)
If this parameter symbol appears, press the SET/ENT key to return to the FUNC menu.
Caution: Do not change the setpoint of the TEST parameter, otherwise the controller will be disabled.
(TEST)
Parameter
Symbol
Name of Parameter
Setting Range and Description
Initial Value
User Setting
Target Item
in CD-ROM
AUTO
Anti-reset windup
(Excess integration
prevention)
AUTO (0), 50.0 to 200.0%
Used when the control output travels up to 100% or down
to 0% and stays at this point.
The larger SP, the sooner PID computation
(integral computation) stops.
(AR)
(ZON)
Point of
on-off action
(Alarm setpoint)
PV value
Output
On
Off
Hysteresis
OFF, 1 to 25, 28 to 31
1: PV high limit (energized, no stand-by action)
2: PV low limit (energized, no stand-by action)
3: Deviation high limit (energized, no stand-by action)
4: Deviation low limit (energized, no stand-by action)
5: Deviation high limit (de-energized, no stand-by action)
6: Deviation low limit (de-energized, no stand-by action)
These Alarm Type parameters are common to the
parameters 1.SP to 4.SP. See List of Alarm Types on the
back for other alarm types.
0: Fixed in green
1: Fixed in red
2: Link to alarm 1 (Alarm OFF:green, Alarm ON:red)
3: Link to alarm 1 (Alarm OFF:red, Alarm ON:green)
4: Link to alarm 1 and 2 (Alarm OFF:green, Alarm ON:red)
5: Link to alarm 1 and 2 (Alarm ON:red, Alarm OFF:green)
6: PV limit (Within PV range:green, Out of PV range:red)
7: PV limit (Within PV range:red, Out of PV range:green)
8: SP deviation (Within deviation:green, Out of deviation:red)
9: SP deviation (Within deviation:red, Out of deviation:green)
Hysteresis for PV high limit alarm
Time
Hysteresis
Alarm setpoint
Alarm output
Delay timer
PV
on
off
Delay timer
●
Input-/Output-related Parameters
Parameter
Symbol
Name of Parameter
Setting Range and Description
Initial Value
PV input type (PV INPUT
terminals)
- - terminals
OFF, 1 to 18, 30, 31, 35 to 37, 40, 41, 50, 51, 55, 56
See Instrument Input Range Codes in
Initial Settings
User’s Manual
.
OFF
—
—
—
—
—
—
—
—
—
—
—
PV input unit
⬚
C: degree Celsius
⬚
F: Fahrenheit
(This parameter is not shown for voltage input.)
⬚
C
Max. value of PV input
range
Min. value of PV input
range
Max. value of
instrument
input range
Min. value of
instrument
input range
Set the PV input range, however RL < RH
-Temperature input
Set the range of temperature that is actually controlled.
- Voltage input
Set the range of a voltage signal that is applied.
The scale across which the voltage signal is actually controlled
should be set using the parameters Maximum Value of PV Input
Scale (SH) and Minimum Value of PV Input Scale (SL).
PV input decimal point
position (displayed
at voltage input)
Max. value of PV input
scale
(displayed at voltage input)
Min. value of PV input
scale
(displayed at voltage input)
0 to 3
Set the position of the decimal point of voltage-mode PV input.
0: No decimal place
1: One decimal place
2 , 3: Two, three decimal places
1
100.0
-1999 to 9999, however SL < SH
Set the read-out scale of voltage-mode PV input.
0.0
User Setting
Target Item
in CD-ROM
(IN)
(UNIT)
(RH)
(RL)
(SDP)
(SH)
(SL)
Selection of PV input
burnout action
External RJC setpoint
OFF
1: Up scale
2: Down scale
-50.0 to 50.0
⬚
C
-58.0 to 122.0
⬚
F
ON
(BSL)
1
0.0
⬚
C
32.0
⬚
F
Presence/absence of
PV input reference
junction compensation
OFF, ON
(RJC)
Control output
type
0
(OT)
13
12
11
0
1
2
3
Time proportional PID relay contact output (terminals - - )
Time proportional PID voltage pulse output (terminals - )
Current output (terminals - )
ON/OFF control relay contact output (terminals - - )
3
2
1
3
2
1
17
16
17
16
(ERJC)
DI function selection
1
(DIS)
Retransmission output
type
1: PV, 2: SP, 3: OUT, 4: Loop power supply for sensor (15 V)
In position proportional control, a valve opening signal (0 to 100%) is
transmitted if setpoint “3” is selected.
In heating/cooling control, an output value before allocation to heating
and cooling control (0 to 100%) is transmitted if setpoint “3” is selected
(0 to 50%: Cooling-side output; 50 to 100%: Heating-side output).
1
Max. value of
retransmission output
scale
Min. value of
retransmission output
scale
RET=1, 2: RTL + 1 digit to 100.0% of PV input range
RET=3: RTL + 1 digit to 100.0%
RET=1, 2: 0.0% of PV input range to RTH - 1 digit
RET=3: 0.0% to RTH - 1 digit
100.0% of
PV input range
0.0% of
PV input range
(RET)
(RTH)
(RTL)
Disables the external contact input.
DI1: 2.SP (on)/1.SP (off), DI2: AUTO (on)/MAN (off)
DI1: Hides (on)/shows (off) the LOCK setup parameter.
DI2: Unused.
See the table below.
DI1: 2.SP (on)/1.SP (off), DI2: STOP (on)/RUN (off)
OFF
1
2
3
4
Control output
type
Continued
Heating/cooling
type: 4
—
Ref.2.2(1)
Ref.3.1(1)
(OT)
The following 4 to 12 are displayed only for heating/ cooling type controllers.
4
5
6
7
8
9
10
11
12
Heating-side relay output (terminals - - ),
cooling-side relay output (terminals - )
Heating-side pulse output (terminals - ),
cooling-side relay output (terminals - )
Heating-side current output (terminals - ),
cooling-side relay output (terminals - )
Heating-side relay output (terminals - - ),
cooling-side pulse output (terminals - )
Heating-side pulse output (terminals - ),
cooling-side pulse output (terminals - )
Heating-side current output (terminals - ),
cooling-side pulse output (terminals - )
Heating-side relay output (terminals - - ),
cooling-side current output (terminals - )
Heating-side current output (terminals - ),
cooling-side current output (terminals - )
3
2
1
7
4
7
4
7
4
3
2
1
3
2
1
17
16
15
14
15
14
15
14
15
14
15
14
15
14
17
16
17
16
17
16
17
16
17
16
Heating-side pulse output (terminals - ),
cooling-side current output (terminals - )
䊊
SP Selection when DIS = 3 is set
DI1
DI2
1.SP
4.SP
3.SP
2.SP
ON
ON
ON
ON
OFF
OFF
OFF
OFF
SELECT display-1
registration
SELECT display-2
registration
SELECT display-3
registration
SELECT display-4
registration
OFF
OFF
OFF, 201 to 1015
Select the desired parameter from among the operating and setup
parameters, then register the number (D register No.) accompanying that
parameter.
For example, registering “231” for C.S1 allows you to change alarm-1
setpoint in operating display.
Numbers for registering alarm SP parameter for operating display:
Alarm-1 setpoint: 231
Alarm-2 setpoint: 232
Alarm-3 setpoint: 233
Above numbers are alarm setpoint parameters for target setpoint-1 (1.SP).
See User’s Manual (Reference) (CD-ROM).
(C.S1)
(C.S2)
(C.S3)
(C.S4)
Key lock
OFF: No key lock
1: Change to any parameter prohibited
Prohibits any operating parameter or setup parameter from being
changed.
The setpoint of the LOCK parameter itself can be changed, however.
2: Change to and display of operating parameters prohibited
Turns off the display for setting operating parameters, thus
prohibiting any change to the parameter settings.
(Hold down the SET/ENT key for more than 3 seconds to show the
password check display.)
3: Disables the A/M key on the instrument’s front panel.
(LOCK)
Password setting
0: Password not set
1 to 9999
0
(PWD)
Ref.6.1(1)
Ref.7.1(2)
Ref.7.1(1)
■
Useful Operating Displays (SELECT Display)
Registering frequently changed parameters in the SELECT display after ordinary operating displays will allow you to change settings easily.
A maximum of four displays can be registered.
Setting method:
Set the parameter numbers (D register numbers) you wish to register
for setup parameters C.S1 to C.S4.
Alarm parameter for target setpoint-1
Registration number
Alarm-1 setpoint parameter
Alarm-2 setpoint parameter
Alarm-3 setpoint parameter
231
232
233
For any registration number other than those above, see User’s Manual
(Reference) (CD-ROM version).
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Heating/Cooling Control (for a Heating/Cooling Controller Only)
In heating/cooling control, the controller outputs the result of computation after splitting it into heating-purpose and cooling-purpose signals.
In addition, the controller can perform PID control or on-off control on the heating and cooling sides separately. When performing on-off
control, set the proportional band to “0”.
The controller splits the result of computation (0 to 100%) into heating-side and cool-
ing-side signals, as described below.
• 0% to 50% of the computation result is presented as a 0% to 100% cooling-side
output.
• 50% to 100% of the computation result is presented as a 0% to 100% heating-side
output.
Heating/cooling control provides two methods in which either none of the heating- and
cooling-side outputs are presented or both of the heating- and cooling-side outputs are
presented, as shown in the following figures.
0
0
Cooling-side
output
Cooling-side
output
Heating-side
output
Heating-side
output
Output (%)
100
Output (%)
100
Deadband (negative)
Deadband (positive)
100(%)
100(%)
50
50
0
0
Value of control output before split into heating- and
cooling-side outputs
Value of control output before split into heating- and
cooling-side outputs
Precautions in Heating/Cooling Control
• Keep the ratio of the heating-side proportional band (P) to the cooling-side proportional band (Pc) equal to or below 5.
• If neither the heating side nor the cooling side is performing on-off control, setting the integral time (I or Ic) of one side to “0” results in
the Integral Time parameters of both sides being set to “OFF”,
irrespective of the integral time setting of the other side.
■
Cycle Time
A cycle time can only be set if the type of control output is time propor-
tional PID relay output or time proportional voltage pulse output.
A cycle time refers to one period consisting of on- and off-state time
lengths. The ratio of the on-state time to the off-state time differs ac-
cording to the value of the control output. The figure on the right shows
on-to-off time ratios of the control output when the cycle time is set to
10 seconds. Setting a shorter cycle time allows the controller to perform
elaborate control at short time intervals. This significantly reduces the
on- and off-state times, however it shortens the service life of a relay.
PV input value
Control output
Interval of auto-tuning
Auto-tuning is
complete when the
3rd peak arrives.
PID control based on
PID constants determined
by auto-tuning
On
Off
On
Setpoint
Time
Start of
auto-tuning
On
Off
2-minute interval of
temperature rise
140
°
C
temperature difference
2 . S P = 6 4 0
°
C
1 . S P = 5 0 0
°
C
70
°
C/min
(140
°
C/2 min) rate of
temperature change
1 . S P
2 . S P
Switching from 1.SP to 2.SP parameter
Time
Maximum value of PV
input range (RH)
Reference point 2
(2.RP)
Minimum value of PV
input range (RL)
Reference point 1
(1.RP)
Zone 3:
Operated with 3rd group of
PID constants
Zone 2:
Operated with 2nd group of
PID constants
Zone 1:
Operated with 1st group of
PID constants
PV input value
Setpoint
S E T / E N T
key
S E T / E N T
key
SP display
OUT display
S E T / E N T
key
Ordinary operating displays (example)
Alarm-1 setting
display (example)
Useful
operating display
(SELECT display)
P V
MAN
A / M
S P
AL1
2
3
SP
2
3
4
S E T / E N T
P V
MAN
A / M
S P
AL1
2
3
SP
2
3
4
S E T / E N T
P V
MAN
A / M
S P
AL1
2
3
SP
2
3
4
S E T / E N T
PID computation
0% to 100%
Heating/cooling
computation
0% to 50%
Cooling-side
output limiter
Cooling-side MV
output 0% to 100%
Heating-side MV
output 0% to 100%
50% to 100%
Heating-side
output limiter
PV
SP
Manual MV output
Communication
On
Off
Cycle time
On
Off
Cycle time
Relay’s Behavior when Cycle Time = 10 sec
For 20% of Control Output
For 50% of Control Output For 80% of Control Output
On-state duration: 2 sec
Off-state duration: 8 sec
On-state duration: 5 sec
Off-state duration: 5 sec
On-state duration: 8 sec
Off-state duration: 2 sec
10 sec
10 sec
10 sec
When using target setpoint ramp setting function, PV tracking works
in case of the above conditions [2] to [5].
NOTE