39
80290C_MHW_2400_0908_ENG
Application Notes
HOLD Function
The input value and alarms are frozen while the logic input is closed.
With logic input closed, a reset turns OFF both the relay outputs and the alarms latch.
FLASH function
The input value is sampled, the setpoints are “frozen”, when the logic input switches on the input value is “frozen”
and the setpoints are updated based on the last acquired value.
time
AL1 + Hy1
AL2 + Hy2
AL2
AL1
alarm 1
alarm 2
(*)
For AL1 = reverse absolute alarm (low) with positive Hyst1, AL1 t = 1
(*) = OFF if disabled on power-up
For AL2 = direct absolute alarm (high) with negative Hyst2, AL2 t = 0
For AL1 = symmetrical Lo absolute alarm with Hyst1, AL1 t = 5
For AL1 = symmetrical Hi absolute alarm with Hyst1, AL1 t = 4
* Minimum hysteresis = 2 scale points
Normal absolute alarm
Symmetrical absolute alarm
reverse
direct
AL1
AL1 + [ Hy1* ]
AL1 - [ Hy1* ]
time
For AL2 = Lo deviation alarm with negative Hyst 2, AL2 t = 3
For AL2 = Hi deviation alarm with negative Hyst 2, AL2 t = 2
For AL2 = Symmetrical Lo deviation alarm with Hyst 2, AL2 t = 7
For AL2 = Symmetrical Hi deviation alarm with Hyst 2, AL2 t = 6
time
AL1+AL2
AL1
reverse
direct
AL1+AL2
AL1
reverse
direct
time
Hy1
Deviation alarm
Symmetrical deviation Alarm
AL1-AL2
Software ON/OFF switching function
How to switch the unit OFF: hold down the “F” and “Raise” keys simultaneously for 5 seconds to deactivate the
unit, which will go to the OFF state while keeping the line supply connected and keeping the process value displayed,
keeping the “OFF” message displayed.
All outputs (alarms and controls) are OFF (logic level 0, relays de-energized) and all unit functions are disabled
except the switch-on function and digital communication.
How to switch the unit ON: hold down the “F” key for 5 seconds and the unit will switch OFF to ON. If there is a power
failure during the OFF state, the unit will remain in OFF state at the next power-up (ON/OFF state is memorized).
The function is normally enabled, but can be disabled by setting the parameter Prot = Prot +16. This function can be
assigned to a digital input (d.i.G), not é subject to the disabilitazione from parameter “Prot” and excludes deactiva-
tion from the keyboard.
Alarms
N.B.: For deviation alarms (At.n = deviation) with different reference quantities (Ar.n), which are set with different decimal points, the switch setpoint always refers
to scale points without considering decimal point.
ex.: if Ar.n = 0 (referred to IN1) and At.n = 6 (deviation referred to IN3) and IN1 with dP = 1, IN3 with dP = 2 AL1 = 200.0 IN3 = 10.00 dS.SP = 1, the alarm
setpoint is 300.0