100
0
100
80
60
40
20
0
100
80
60
40
20
0
25
50
75
Standard Functions
Optional Functions
This function limits the highest output for the period of a
preset time after power-ON and control mode change from
Stop to Run. It makes the THW Series suitable for heaters
which cause rush current flow, such as Halogen lamp,
Tungsten, Platinum, and Molybdenum heaters.
Output limiter High at start-up
100
80
60
40
20
0
High limiter at
the time of start
100
0
100
80
60
40
20
0
25
50
75
The contact input can be configured to Run/Stop,
Auto/Manual or alarm interlock reset. The alarm types
are reverse phase detection, power frequency
abnormal, and FAIL. Alarm output will go on, when any
of them goes in alarm status. Optional heater break
alarm and over-current alarm can be also configured as
an output (alarm logic selection).
16mA
20mA
8mA
12mA
Input signal
100
80
60
40
50
20
0
100
80
60
40
20
0
Input signal
Input signal
100
80
60
40
20
0
Output current (%)
Output current (%)
16mA
12mA
8mA
20mA
This function maintains the output current constant when a
load or a power supply fluctuates. It makes the THW
Series suitable for heaters of which resistance greatly
changes by temperature change, such as Platinum,
Molybdenum, Tungsten, and Tantalum heaters.
This function controls the output to make its effective value
power proportional to the input. It makes the THW Series
suitable for heaters of which resistance gradually
increases by temperature or time, such as silicon carbide
type heater.
This function controls its effective value power at 50% of
the rating shown in the diagram below.
100
25
50
75
0
Load
(%)
100
80
60
40
20
0
Limiter set value
30%
60%
100%
Constant current control
Constant power control
Constant voltage control
0
20
40 50 60
80
100
20mA
16mA
12mA
8mA
5mA
300%
200%
100%
0
60%
Soft start
Soft start
100
25
50
75
0
The relation between the setting input and the output
voltage can be set. Gradient setting is possible via front
keys or an external setter. Control characteristics may
vary with the setting as follows.
Gradient setting output characteristic diagram
Gradient setting
Input signal (%)
1. Auto setting input X Internal gradient setting X External gradient setting
2. Auto setting input X Internal gradient setting
3. Manual setting X Internal gradient setting X External gradient setting
Output
voltage
(%)
Gradient
setting
Even if setting input changes abruptly, output changes
slowly to suppress inrush current. Ramp-up (Start-up) and
ramp down (Start-Down) time can be set in the range of 0.1
to 99.9 sec via front keys.
Time
Soft-start
time
Soft-down
time
100%
Time
Ramp function (Soft-start & Soft-down)
Output
voltage
(%)
Input
signal
Soft-start & Soft-down action diagram
When phase control is selected for linear load (R: resistor),
output mode can be selected among Proportional phase
angle to input, proportional voltage to input, and
proportional square voltage (electric power) to input.
Three types of output modes
100
50
0
4
12
20
4
12
20
4
12
20
100
50
0
100
50
0
Input signal (mA)
Input signal (mA)
Input signal (mA)
Proportional phase
angle to input
Proportional
voltage to input
Proportional square
voltage (electric power)
to input
* Default setting is proportional square voltage to input.
Phase
angle
(%)
(%)
(%)
Effective
voltage
Electric
power
Output highest and lowest values can be set via front
keys.
Output limiter (High & Low)
100
0
100
80
60
40
20
0
80%
80%
25
50
75
High limiter
High limiter
10%
Low limiter
Input signal (%)
Output
voltage
(%)
Output
voltage
(%)
High & Low limiter characteristic diagram
Output bias can be set via front keys.
(Base-up setting is valid when output limiter low is set to
0.0)
Input signal (%)
Base-up setting (Output bias)
Base-up
setting : 20%
Output
voltage
(%)
Output
voltage
(%)
Output
voltage
(%)
Output
voltage
(%)
Base-up output characteristic diagram
This function measures load current and compares it with
a heater break alarm set value. Alarm will be activated if
the load current goes into alarm ranges. UP to two alarm
set points can be set for the heater break alarm, which
could be used for heater-deterioration alarm and heater-
break alarm.
Heater break alarm
Fuse break alarm
Over-current alarm
(Note) For phase control alarm does not work when the load
current is less than 15% of maximum load current.
This function limits the load current value to the heater.
The setting range is 30 to 100% of the rated current.
Load current limiter
(Note) If the load has a large inrush current, use soft-start function
along with this function to suppress the inrush current.
This function alone can not prevent the inrush current.
(For phase control
only)
(For phase control
only)
(For phase control
only)
Current limiter characteristic diagram
Output
current
The alarm goes on when the load current exceeds 120%
of the rated current.
High limiter output
at the time of start
Event input and alarm function
Constant current control characteristic diagram
Constant power control characteristic diagram
Output current (%)
Constant voltage control characteristic diagram
This function maintains the output voltage constant when
a load or a power supply fluctuates.
(For phase control
only)
The alarm goes on when a fast blown fuse is blown. The
fuse with alarm output function must be used for this
function.
