set
set
SP2L
s will
e last
lly
y to
the
ut. To
ALARM TYPE AND ACTION
Caution: In any critical application where failure could cause expensive product loss or
endanger personal safety, a redundant limit controller is required.
When setting an alarm value for an absolute alarm (
A1t
=
AbS
or
A2t
=
AbS
),
simply set the value at which the alarm is to occur.
When setting the alarm value for a deviation alarm (
A1t
=
dE
or
A2t
=
dE
), set the
difference in value from the Set Point (
SP1H
) desired.
Since the input for the MPC is driven from a transmitter, the input display can be
programmed in different ways. Regardless of the position of the decimal point, a change of
one in the right most digit is referred to as a count. For example, if there were no decimal
point selected, a change from 235 to 236 is a change of one count. If the decimal point
were selected at
0.0
, a change of 23.5 to 23.6 is a change of one count.
When setting up an alarm for deviation the deviation is set in counts. For example if a low
alarm is required to be 5 counts below the
SP1H
, then set
A
#
Lo
to -5. If a high alarm is
required 20 counts above the
SP1H
, then set
A
#
Hi
to +20. If
SP1H
is changed, the alarm
will continue to hold the same relationship as originally set.
When Alarm Power Interrupt,
A
#
P
, is programmed ON and Alarm Reset,
A
#
rE
, is
programmed for Hold, the alarm will automatically reset upon a power failure and
subsequent restoration if no alarm condition is present.
If Alarm Inhibit,
A
#
iH
is selected ON, an alarm condition is suspended upon power up until
the process value passes through the alarm set point once. Alarm inhibit can be restored
as if a power up took place by pressing both the INDEX and ENTER keys for 5
seconds.
WARNING: IF INHIBIT IS ON AND A POWER FAILURE OCCURS DURING
A HIGH ALARM, RESTORATION OF POWER WILL NOT CAUSE THE
ALARM TO OCCUR IF THE PROCESS VALUE DOES NOT FIRST DROP
BELOW THE HIGH ALARM SETTING. DO NOT USE THE ALARM INHIBIT
FEATURE IF A HAZARD IS CREATED BY THIS ACTION. BE SURE TO
TEST ALL COMBINATIONS OF HIGH AND LOW ALARM INHIBIT ACTIONS
BEFORE PLACING CONTROL INTO OPERATION.
The following menu items apply only to the alarms.
AL1
Alarm 1 function: Select
0FF
,
Lo
,
Hi
, or
HiLo
. Factory default is
Hi
.
0FF
Alarm 1 is disabled. No Alarm 1 menu items appear in the
Secondary or Secure menus.
Lo
Low Alarm Only.
A1Lo
appears in the Secondary Menu.
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