Alert Alarms - Mitsubishi Electric MELSECSystem Q User Manual

3 SPECIFICATIONS

3.2.11 Alert alarms

1) Upper limit input alert
When the process value (PV) is equal to or greater
than the alert set value, the system is put in an alert
status.
Process value (PV)
Alert set value
Alert status
[When alert set value is positive]
Process value (PV)
Alert set value
Temperature
set value (SV)
Alert status
3 - 15
(1) The alert alarm is a function which sets the system in an alert status when the
process value (PV) or deviation reaches the alert set value. It is used to turn on
the device's hazard signal or operate the safety device.
The alert alarm is classified as follows:
• Input alerts ............. Upper limit input alert, lower limit input alert
• Deviation alerts...... Upper limit deviation alert, lower limit deviation alert,
(a) Input alerts
Process value (PV)
(b) Deviation alerts
1) Upper limit deviation alert
When the deviation [process value (PV) - set value (SV)] is equal to or
greater than the alert set value, the system is put in an alert status.
Process value (PV)
upper/lower limit deviation alert, within-range alert
2) Lower limit input alert
When the process value (PV) is equal to or less
than the alert set value, the system is put in an
alert status.
Process value (PV)
Alert set value
Time
Alert status
Process value (PV)
Temperature
set value (SV)
Alert set value
Time
Alert status
MELSEC-Q
Process value (PV)
Non-alert status
[When alert set value is negative]
Process value (PV)
Non-alert status Alert status
Time
Alert status
Time
3 - 15