Section 3 Basic Operations
3-6
Basic
Operations
3.4 Setting Output Specifications
■ Control Period
• Set the output period (control period). 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.
• The control period can be set to either 2 s or 20 s using the control
mode switch 2. The default is OFF (20 s).
• The control period can also be set to 6 s or 60 s by changing the
control period setting in the initial setting level (1).
■ Direct/Reverse
Operation
• “Direct operation” increases the manipulated variable whenever the
process value increases. “Reverse operation” decreases the
manipulated variable whenever the process value increases.
Manipulated variable
100％
0％
Set point
Low
temperature
High
temperature
Manipulated variable
100％
0
Set point
Low
temperature
High
temperature
Direct operation Reverse operation
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.
• Set using the control mode switch 3. The default is OFF (reverse
operation).
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