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4 Basic Operation
E5@C Digital Temperature Controllers User’s Manual (H174)
4-6 Setting Output Specifications
4
4-6-1 Control Periods (Not Supported for Position-proportional Models.)
4-6 Setting Output Specifications
4-6-1 Control Periods (Not Supported for Position-proportional
Models.)
• Set the output periods (control periods). Though a shorter period provides
better control performance, it is recommended that the control period be set to
20 seconds or longer for a relay output to preserve the service life of the relay.
After the settings have been made in the initial setup, readjust the control
period, as required, by means such as trial operation.
• Set the control periods in the Control Period (Heating) and Control Period
(Cooling) parameters in the Initial Setting Level. The default is 20 seconds for
a relay output and 2 seconds for a voltage output (for driving SSR).
• The control periods are used only for PID control.
• The Control Period (Cooling) parameter is used only for heating/cooling
control.
• When control output is used as a linear current output, the Control Period
parameter cannot be used.
4-6-2 Direct and Reverse Operation
• Direct operation increases the manipulated variable whenever the process
value increases. Reverse operation decreases the manipulated variable
whenever the process value increases.
For example, when the process value (PV) is lower than the set point (SP) in a
heating control system, the manipulated variable increases according to the
difference between the PV and SP. Accordingly, reverse operation is used in a
heating control system. Direct operation is used in a cooling control system, in
which the operation is the opposite of a heating control system. The Control
Output 1 Assignment is set to o (control output (heating)) for either direct or
reverse operation.
• Direct/reverse operation is set in the Direct/Reverse Operation parameter in
the Initial Setting Level. The default is or-r (reverse operation).
cp
c-cp
Control Period
(Heating)
Control Period
(Cooling)
orev
100%
0%
100%
0%
Manipulated variable
Manipulated variable
Low
temperature
Set Value
High
temperature
Low
temperature
Set Value
High
temperature
Direct operation
Reverse operation
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