Extech Instruments 96VFL

30 VFL Series User Manual v2.3 12/20
ALARM STANDBY AND LATCH SPECIALTY MODES
‘A1md’ / ‘A2md’ setting
Operation
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 (Event and Soak Timers)
The alarm relays can be used as ON (Event) or OFF (Soak) Timers as explained below.
For ON (Event) 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 (this is the ‘Event’).
For OFF (Soak) 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 (the ‘Soak’ begins). When
the timer counts down, the relay switches OFF (the ‘Soak’ ends). See the table below:
Relay Action for ON and OFF Timers
Controller at power-up
Timer Starts (PV=SV)
Timer Stops
ON TIMER
Relay OPEN (OFF)
Relay stays OFF
Relay CLOSES (ON)
OFF TIMER
Relay OPEN (OFF)
Relay CLOSES (ON)
Relay OPENS (OFF)
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.