K8AC-H
9
Wiring Method When Using the K8AC-H with Cyclic Control Heaters
Wiring Method When Using the K8AC-H with Phase Control Heaters
SSR
SSR
CT2
CT1
3
7
8
9
10
12 11
13 14
1
2
RS-485
4
5
6
5
6
3
4
Transistor Output
K8AC-H2
@@
N-FLK
Heater
*
Power supply
G32A-EA
Cyclic
Control Unit
Temperature
Controller
4 to 20 mA current output
Operation Description
• If the heater current detected at either CT1 or CT2 falls below the
burnout alarm set value, an alarm is output. The burnout alarm set
value can be set separately for CT1 and CT2.
No burnout alarm is output, however, when the temperature con-
troller control output is OFF.
Burnouts are detected only while the temperature controller control output
is being input to the gate input terminals (11 and 12). Burnout is detected
with no errors because the automatic adjustment of burnout alarm level is
linked to the temperature controller control output (4 to 20 mA).
• Burnout is detected when control outputs from the temperature con-
troller are 7 mA min.
Correct Usage
• Always take the power supply voltage from the primary side of the SSR.
• Use a temperature controller with a 4 to 20-mA current output.
• When you adjust the set value for the burnout alarm, make sure
that you make the setting with the temperature controller's control
output at a 100% output.
The burnout detection value is the detection value at 100% output.
Therefore, correct operation will not be possible if the setting is
made based on a measurement value when the output is not 100%.
• CT1 and CT2 are special products. Use K8AC-CT
@@
.
• The CTs do not have polarity.
• Connect only one CT for single-phase heaters.
• Connect two CTs for three-phase heaters.
• For three-phase heaters, always set the burnout alarm set values
for both CT1 and CT2.
*
Consult with your OMRON representative if multiple heaters are connected
in parallel different heater capacities, or if a heater with varying heater
resistance is used.
CT2
CT1
3
7
8
9
10
12 11
13 14
1
2
RS-485
4
5
6
5
6
3
4
Transistor Output
K8AC-H2
@@
N-FLK
Heater
*
Power supply
Power
Regulator
Temperature
Controller
4 to 20 mA current output
Operation Description
• If the heater current detected at either CT1 or CT2 falls below the
burnout alarm set value, an alarm is output. The burnout alarm set
value can be set separately for CT1 and CT2.
No burnout alarm is output, however, when the temperature con-
troller control output is OFF.
Burnouts are detected only while the temperature controller control
output is being input to the gate input terminals (11 and 12).
Burnout is detected with no errors because the automatic adjust-
ment of burnout alarm level is linked to the temperature controller
control output (4 to 20 mA).
• Burnout is detected when control outputs from the temperature con-
troller are 7 mA min.
Correct Usage
• Always take the power supply voltage from the primary side of the
contactor.
• Use a temperature controller with a 4 to 20-mA current output.
• When you adjust the set value for the burnout alarm, make sure
that you make the setting with the temperature controller's control
output at a 100% output (20 mA).
The burnout detection value is the detection value at a 100% out-
put. Therefore, correct operation will not be possible if the setting is
made based on a measurement value when the output is not 100%.
• Adjust the burnout alarm set value at a 100% output for gradient
settings as well.
• If using the soft startup function with a power regulator, set the soft
startup function on the K8AC-H as well, to prevent malfunctions.
• CT1 and CT2 are special products. Use K8AC-CT
@@
.
• The CTs do not have polarity.
• Connect only one CT for single-phase heaters.
• Connect two CTs for three-phase heaters.
• For three-phase heaters, always set the burnout alarm set values
for both CT1 and CT2.
• When using the power regulator's gradient settings, change the
operation gate current level so that the heater current value is
within the measurement range. (The initial value is 7 mA.)
For details on operating methods, refer to pages 16 to 18.
*
Consult with your OMRON representative if multiple heaters are connected
in parallel different heater capacities, or if a heater with varying heater
resistance is used.
