Omron K2CU Manual page 3

K2CU
Operation
K2CU-F A- GS Series
When power is supplied to the heater (when the SSR is ON), a cur-
rent flows through the wires to the heater elements. At the same
time, a voltage is imposed on the gate circuit and the
K2CU-FjjAjGS begins monitoring the current flowing through
the heater wires.
The current flowing to the heater wires is detected by the detector
sections through each Current Transformer (CT) incorporated by
the K2CU-FjjA-jGS.
The current signals transmitted by the two CTs are sent to the cur-
rent-voltage converters, smoothing circuits, and comparators as
shown in the diagram.
Power source
SSR
CT
1
Current-
voltage
converter
CT
2
Current-
voltage
converter
Note: 1. The dotted lines indicate the line conductors passing through the windows of the current transformers.
2. The current flowing into the gate circuit (between G+ and G–) is as follows:
Heater elements
3 When using a K2CU which has the model number suffix "GS" (a model that incorporates gate input
G+ G–
Smoothing
circuit
Gate
circuit
Smoothing
circuit
Approximately 1.4 mA at 5 VDC
Approximately 3.4 mA at 12 VDC
Approximately 6.7 mA at 24 VDC
terminals), the control output of the temperature controller must be a voltage output type.
The signal generated by the reference voltage generator is sent to
the setting circuit to provide a reference value. The reference value
is sent to the comparators. Each comparator compares its heater
element current input and the reference value. If the input is lower
than the reference value, a signal is sent to the output circuit.
There are two detector sections operating independently. If either of
the input signals from the CTs is lower than the reference value, the
output relay and alarm indicator will be activated.
The K2CU-FjjA-jGS incorporates a voltage fluctuation com-
pensation function which automatically corrects the reference value
if the supply voltage fluctuates.
Temperature
DC
controller
Comparator Setting Reference
circuit voltage
generator
Comparator Output
circuit
K2CU
S1 S2
Power
circuit
b1
To each circuit
X/c
a1
X CM1
Output relay
Alarm indicator
Buzzer
BZ
3