63
SC-F70
SC-F70
PID Operation Operating Instructions
∑∑∑∑∑
Types of Alarm
The following types of alarms can be selected by setting the
parameters PG04/ALGr for each alarm, AL1 to AL4. See page 73.
When you select a type of alarm, alarm control values are initialized
to their defaults, as shown in the next table. If needed, you can
change the settings to the values that best suit your requirements.
Description
Alarm is not used.
Alarm activates when measurement value exceeds the
upper limit of the range.
Alarm activates when measurement value exceeds the
lower limit of the range.
Alarm activates when deviation value exceeds the preset
value (PV > SV).
Alarm activates when deviation value goes below the
preset alarm value (PV < SV).
Alarm activates when deviation exceeds either upper or
lower limits.
Alarm activates when deviation value stays within the
preset alarm value.
Same as Type 1 with standby operation (Note 2).
Same as Type 2 with standby operation (Note 2).
Same as Type 3 with standby operation (Note 2).
Same as Type 4 with standby operation (Note 2).
Same as Type 5 with standby operation (Note 2).
Alarm activates when input error occurs (Note 4).
Alarm activates when a failure is detected (FAIL lamp lit)
(Note 3).
Default value
set in PG02
Not set/
Not displayed
Upper limit
Lower limit
Measurement
span (Note 1)
Measurement
span (Note 1)
Measurement
span (Note 1)
Measurement
span (Note 1)
Upper limit
Lower limit
Measurement
span (Note 1)
Measurement
span (Note 1)
Measurement
span (Note 1)
Not set/
Not displayed
Not set/
Not displayed
Type
0
1
2
3
4
5
6
7
8
9
10
11
12
13
Notes:
1. The Measurement span is the difference between the upper and lower limits of the
measurement range (upper limit minus lower limit). Differential greater than
9999 is limited to 9999.
2. The Standby operation ignores the alarm if the alarm condition occurs
immediately after the target value is changed. When the measurement value drops
within the normal range, however, and then the alarm condition is again satisfied,
the alarm is activated. As a result, the standby operation separates a real alarm
from a usual time lag alarm because of a sudden target change.
3. Alarm relay contact is open for no alarm state, and is closed when alarm conditions
are met.
4. Inputs to be monitored are measurement input, analog setting input, and area
switching input.