Nor-Cal SDC15 Controller - Manual (Page 93)

5-43
Chapter 5. DETAILED DESCRIPTION OF EACH FUNCTION
Operation type Set value Direct action Reverse action
of operation
type
Loop diagnosis 3 22
High limit
Low limit
Time
Conditions 3
ON delay
set time
Conditions 3
ON delay
set time
ON delay is started when conditions 1 and 2 are satisfied.
Area satisfying
conditions 2
Area satisfying
conditions 2
Time
Time
PV
MV
EV
ON ON
HYS
HYS
PV to be used
as reference
PV to be used as reference
(0 or more)
Main setting
Main setting (0 or more)
Area satisfying
conditions 1
Area satisfying
conditions 1
High limit
Low limit
Time
Conditions 3
ON delay
set time
Conditions 3
ON delay
set time
ON delay is started when conditions 1 and 2 are satisfied.
Area satisfying
conditions 2
Area satisfying
conditions 2
Time
Time
PV
MV
EV
ON ON
HYS
HYS
(0 or more)
Main setting
Main setting (0 or more)
Area satisfying
conditions 1
Area satisfying
conditions 1
PV to be used
as reference
PV to be used
as reference
The event is turned ON when any change in PV corresponding to increase/decrease in MV
(Manipulated variable) is not observed. This event is used to detect any fault at the operation
end.
● Setting items
• Main setting: Change in PV from the point that the MV reaches the high limit (100%) or low
limit (0%).
• Sub-setting: Range of absolute value of deviation (PV-SP) allowing the event to turn OFF.
• ON delay time: Diagnosis time
• OFF delay time: A period of time from power ON allowing the event to hold OFF state.
● Operation specifications
The direct action is used for the heat control and is turned ON in the following cases:
• The increase in PV becomes smaller than the main setting after the diagnosis time (ON
delay time) has elapsed after the MV had reached the high limit.
• The decrease in PV becomes smaller than the main setting after the diagnosis time (ON
delay time) has elapsed after the MV had reached the low limit.
The reverse action is used for the cool control and is turned ON in the following cases:
• The decrease in PV becomes smaller than the main setting after the diagnosis time (ON
delay time) has elapsed after the MV had reached the high limit.
• The increase in PV becomes smaller than the main setting after the diagnosis time (ON
delay time) has elapsed after the MV had reached the low limit.
In the following cases, the event is turned OFF with the priority over the above conditions:
• The absolute value of the deviation (PV-SP) becomes less than the sub-setting.
However, the event is turned OFF when the absolute value of the deviation is less than the
(sub setting – hysteresis) value after the absolute value of the deviation has become the sub
setting or more.
• A period of time after the operation has been started by power ON is less than the OFF
delay time.
● CAUTION
When setting the ON delay and OFF delay, it is necessary to put in " High function
configuration".
The default settings of the ON delay and OFF delay before shipment are 0.0s.
Heat control Cool control