Azbil C1M - Page 118

5-60
Chapter 5. Functions
Operation type Setting Direct action Reverse action
Loop diagnosis 3 22 Turns on when the PV does not change according to the increase or decrease of the MV.
Use this setting to detect a failure of the actuator, etc.
zSettings
• Main setting: the amount of a change in the PV from the time when the MV reaches the
high limit (100 %) or the low limit (0 %)
• Sub-setting: the absolute value of deviation (PV−SP) that will turn off the event
• ON delay time: diagnosis time
• OFF delay time: time from power-on to event OFF
zOperation specifications
In a direct operation of heating control, the event turns ON if:
• The amount of PV increase after the diagnosis time (ON delay time) elapses after the MV
reaches the high limit is smaller than the main setting.
• The amount of PV decrease after the diagnosis time (ON delay time) elapses after the MV
reaches the low limit is smaller than the main setting.
In a reverse operation of cooling control, the event turns ON if:
• The amount of PV decrease after the diagnosis time (ON delay time) elapses after the MV
reaches the high limit is smaller than the main setting.
• The amount of PV increase after the diagnosis time (ON delay time) elapses after the MV
reaches the low limit is smaller than the main setting.
The conditions below have priority over the conditions above, and if any of these conditions
is met, the event will turn OFF.
• The absolute value of deviation (PV−SP) is smaller than the sub-setting
However, after the absolute value of deviation exceeds the sub-setting, the event turns
OFF if the absolute value of deviation becomes smaller than the value obtained by
subtracting the hysteresis from the sub-setting.
• The time from the start of operation after power-on is less than the OFF delay time
zNote
To set the ON and OFF delay times, the user level (C79) should be set to “advanced
configuration.”
The ON and OFF delay times are set to 0.0 s when the product is shipped.
For heating control
If cond. 1 & 2 are met, ON delay starts
High
limit
Low
limit
Time
Cond. 3
ON delay time
Area meeting
cond. 2
Area meeting
cond. 2
Time
Time
PV
MV
EV
ON ON
HYS
HYS
Reference
PV
Reference PV
Area
meeting
cond.1
Area
meeting
cond.1
Main setting
(if 0 or more)
Main setting
(if 0 or more)
For cooling control
If cond. 1 & 2 are met, ON delay starts
Time
Time
Time
PV
MV
EV
ON
HYS
HYS
ON
Cond. 3
ON delay time
Cond. 3
ON delay time
Area meeting
cond. 2
Area meeting
cond. 2
Area
meeting
cond.1
Area
meeting
cond.1
High
limit
Low
limit
Reference
PV
Main setting
(if 0 or more)
Main setting
(if 0 or more)
Reference
PV