16
AB-6600
< Heating two-step control >
Based on the heating control system shown in Figure 18. Example of wiring for heating two-step control,
operation of Model TTY6800Z thermostat is described assuming the temperature setpoint: 50 °C, differential
gap: 3 °C, differential between two switches: 8 °C.
(1) When the temperature of the controlled target falls to 55 °C, that is setpoint (50 °C) plus the differential
between two switches (8 °C) minus the differential gap (3 °C), the switch 2 works to close the terminal R2
and W2, and then the heater 1 starts.
(2) Along with operation of heater 1, when temperature of the controlled target rises to 58 °C, that is setpoint (50
°C) plus the the differential between two switches (8 °C), and then the heater 1 stops.
(3) Although the heater 1 keeps operating, if the temperature of the controlled target keeps falling and it
reaches 47 °C , that is setpoint (50 °C) minus the differential gap (3 °C), the switch 1 works to close the
terminal R1 and W1, and then the heater 2 starts.
(4) Along with operation of heater 1 and heater 2, when temperature of the controlled target rises to 50
°C, the switch 1 works to open the terminal R1 and W1, and then the heater 2 stops.
Only the heater 1 operates.
(5) When the temperature of the controlled target rises further to 58 °C, that is setpoint (50 °C) plus the
differential between two switches (8 °C), and then the chiller 1 stops.
(6) When the temperature of the controlled target falls again, the steps from (1) will be carried out
automatically.
Figure 29. Example of heating two-step control
z
Operation check
IMPORTANT
•
Because of delayed response of the sensor, the differential gap may seem to be large.
As necessary, adjust the mounting location, etc. to eliminate delayed response.
(1) Turn on the power to the product.
(2) Turn the setting knob to the setpoint.
(3) Check that the control target equipment normally runs or stops as intended.
(4) Turn off the power to the product.
50
(Setpoint)
585547
(3) (4)
(1),(5) (2)
Heater 1 ON
Between R1 and W1: Open
Between R1 and B1: Close
Heater 1 OFF
Between R1 and W1: Close
Between R1 and B1: Open
Temperature of sensor [ °C]
Heater 2 ON
Between R2 and W2: Open
Between R2 and B2: Close
Heater 2 OFF
Between R2 and W2: Close
Between R2 and B2: Open
Differential between two switches
8 °C
Switch 2
Differential gap
3 °C
Switch 1
Differential gap
3 °C
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