IDEC MicroSmart Pentra - Manual (Page 98)

C ONFIGURING PID M ODULE USING W IND LDR
F C5A MicroSmart PID Module User’s Manual FC9Y-B1283 6-33
(9) Control Register+73: Alarm 1 Hysteresis
Control Register+74: Alarm 2 Hysteresis
Control Register+75: Alarm 3 Hysteresis
Control Register+76: Alarm 4 Hysteresis
Control Register+77: Alarm 5 Hysteresis
Control Register+78: Alarm 6 Hysteresis
Control Register+79: Alarm 7 Hysteresis
Control Register+80: Alarm 8 Hysteresis
When an alarm turns from on to off and vice versa, the span between on and off is called alarm hysteresis. If
the alarm hysteresis is narrowed, the alarm output switches to on or off even by a slight variation of
temperature at around the alarm action point. This frequent on/off of an alarm may negatively affect the
connected equipment. To prevent that harmful effect, configure the alarm hysteresis for alarm on/off action.
(10) Control Register+81: Alarm 1 Action Delay Time
Control Register+82: Alarm 2 Action Delay Time
Control Register+83: Alarm 3 Action Delay Time
Control Register+84: Alarm 4 Action Delay Time
Control Register+85: Alarm 5 Action Delay Time
Control Register+86: Alarm 6 Action Delay Time
Control Register+87: Alarm 7 Action Delay Time
Control Register+88: Alarm 8 Action Delay Time
The alarm is not triggered until the configured time elapses after the process variable (PV) enters the alarm
output range. The input fluctuation due to noise may result in alarm output turning on. This can be prevented
by configuring the alarm delay time. When an alarm output is changed from on to off status, the alarm output
turns off and the alarm action delay time is reset. When the alarm output is changed from off to on status, the
time counting starts.