VFL Series User Manual v2.0 10/20
ALARM STANDBY AND LATCH MODES
Normal alarm mode. When an ON or OFF Timer function is
selected, with the PV<SV, the timer function is disabled.
Standby mode (start-up inhibit). For any alarm function, this
will prevent an alarm trip when there is an alarm condition
upon power up. The alarm will not trigger the first time the
PV reaches the alarm setpoint. This helps avoid alarm trips
during startup.
Latch mode. When selected, the alarm output and indicator
remain ON even after the alarm condition has been cleared
(unless the power to the meter is removed). Select ‘none’ to
release the latch.
Standby and Latch modes both active.
11.4 ON-OFF Alarm Timers
The alarm relays are normally open (N.O.) dry contact switches. In normal operation, in a non-
alarm state, alarm relays are open (OFF). The alarm relays can be used as ON or OFF Timers as
explained below.
For ON Timers, the alarm relays are normally open (OFF). When the PV reaches the SV, the
timer starts counting (relay is still OFF). When the timer counts down, the relay switches ON.
For OFF Timers, the alarm relays are normally open (OFF), but they close (switch ON) when the
PV reaches the SV. At that point, the timer starts counting. When the timer counts down, the
relay switches OFF. See the table below:
Relay Action for ON and OFF Timers
Set the ‘A1Fu’ or ‘A2Fu’ Alarm function to ON Timer (‘t.on’) or OFF Timer (‘t.off’) in Menu 4,
Options.
Set the time format (MM:SS or HH:MM) using the ‘P.tme’ parameter in Menu 4. Lastly, set the
time in the A1SP (for Alarm 1) or A2SP (Alarm 2) parameter in Menu 1, User level.
Alarm Timers are typically used as Soak or Event timers. In Soak applications, a process stage
may need to remain steady for a specific time (soak time). An OFF timer is handy in such a
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