User manual

4
Note 1: an external 250Ω precision resistor is needed for current input.
Note 2: factory setting: PT100 input. It is adjustable for linear input and feedback ranges. The default range of
input feedbadk is –999~9999. For example, when a 0~20mA analog input is selected as the input
temperature sensor type, -999 indicates 0mA and 9999 indicates 20mA. If change the input range to
0 ~ 2000, then 0 indicates 0mA and 2000 indicates 20mA. One display scale is equal to 0.01mA.
6 OUTPUT FUNCTION
Output control for DTC is selective: Control output (heating, cooling), Alarm output, or
Retransmission output.
Control Output:
Temperature can individually be controlled by two groups outputs: cooling (forward) or heating
(reverse). When Dual Loop output control is used, two output controls shall be designed for cooling
(forward) or heating (reverse). If two control outputs with the same direction are performed, only 1
st
group control period is valid. Control methods: PID control, ON/OFF control, Manual control, and
PID program control.
Single-output Control:
Heating Hysteresis
ON
OFF
PV
Figure1: ON-OFF control of single output
Cooling Hysteresis
Heating Cooling
Set Point
Set Point
PV
100%
0
PV
100%
0
Output
Heating
Set Point
Output
Cooling
Set Point
Figure 2: PID Control,
forward (cooling) control
Figure 3: PID Control,
reverse (heating) control
Dual Output Control:
OFF
PV
Set point
ON
Heating
Dead band
Heating hysteresis
Figure 4.
of dual loop output
ON-OFF control
Cooling hysteresis
Cooling