Omron G3ZA Manual page 4

Applicable SSR and Control
Methods
V2
The G3ZA can be used for a variety of applications by selecting the
SSR drive. For example, inrush current can be reduced at startup by
selecting soft-start optimum cycle control if a single-phase halogen
heater is used.
SSR Control
method
Single-phase Optimum cycle
heater SSR control
with zero-
cross function
Single-phase Soft-start
heater SSR optimum cycle
without zero- control
cross function
Three-phase Three-phase
heater SSR optimum cycle
with zero- control
cross function
Optimum Cycle Control
• Optimum cycle control is performed by driving SSRs according to
load power detection and trigger signals. (Zero-cross SSRs are
used.)
• Noise is suppressed while ensure high-speed response by turning
outputs ON and OFF each half cycle to achieve high-precision
temperature control.
1/5th ON (20%)
Manipulated
variable: 20%
Note: Refer to Connection Configuration on page 6 for connecting to
an SSR.
Soft-start Optimum Cycle Control
• Soft-start optimum cycle control is a control method that combines
phase control and optimum cycle control.
• Smooth switching for phase control and optimum cycle control
enables control of outputs with limited inrush current even for loads
with characteristics like halogen heaters.
• Use a single-phase heater SSR (without the zero-cross function)
for soft-start optimum cycle control. Refer to G3PA on page 11 for
details on SSRs without the zero-cross function.
• Control is switched according to the Control Switching MV Thresh-
old.
• Set the Soft-start Up/Down Time to control output.
• Current is not detected during phase control. The current value
(heater ON current value, heater OFF current value, and effective
current value) will be 0 A, and the current error alarm (heater burn-
out detection, SSR short-circuit detection, and heater overcurrent
detection) will always turn OFF.
4
Multi-channel Power Controller
CT (4-channel Example of
models only) supported
heater
0 to 50 A or 0 SIngle-phase
to 150 A: 4 heater
Units
0 to 50 A or 0 Single-phase
to 150 A: 4 halogen
Units heater
0 to 50 A or 0 Three-phase
to 150 A: up to heater
2 Units
V2
G3ZA
Setting the Control Switching MV Threshold
The Control Switching MV Threshold function is enabled when soft-
start optimum cycle control is used. Setting the Control Switching MV
Threshold enables switching to phase control when the current value
is below the set value, and switching to optimum cycle control when
the current value is above the set value. The default setting is 20.0%.
Variable
type
85/C5 Ch1 to Ch8 Control
Switching MV
Threshold
Example: For channel 1, soft-start optimum cycle control is
performed under the following conditions: control switching MV:
40.0%, MV: 100.%, soft startup time: 20 s.
(1) Ch 1 Control Switching MV Threshold is set to 40.0% and Ch1
V2
MV is set to 100.0% by writing to the variable area.
(2) Ch1 Soft Startup Time remains at the default. Setting is not
required.
(3) Once the Control Switching MV Threshold is written, the
V2
changes are saved and become enabled the next time the
power is turned ON.
MV
100.0%
40.0%
Soft startup time (20 s)
Phase control
Three-phase Optimum Cycle Control
V2
• Three-phase optimum cycle control is a control method that turns
the output ON and OFF every two cycles.
• Turning the output ON and OFF every two cycles enables optimum
cycle control for three-phase heaters.
• Use a three-phase heater SSR with a zero-cross function for three-
phase optimum cycle control.
Note: Refer to page 6 for details on connecting to three-phase
heaters.
The following figure shows the current waveform of each phase for a
MV of 50% when a three-phase heater SSR is connected.
Load power
supply
R-S phase
S-T phase
R-T phase
Parameter Setting
range
0.0% to
100.0%
Optimum cycle control
Default
20.0
Time