19
CAUTION
When the 4/20mA supply is removed
both alarm outputs will open
irrespective of conditioning.
Therefore for fail safe operation both
alarm outputs should be
programmed to be open in the alarm
condition.
To check or change the alarm output status select
'no.nc' from the alarm menu and press
P
reveal the
current setting. The function can be changed by
pressing the
Up
or
Down
button followed by the
E
button to return to the alarm menu.
9.2.8 Hysteresis: HStr
During programming hysteresis is shown in the
units the indicator has been calibrated to display.
To adjust the hysteresis, select 'HStr' from the
alarm menu and press
P
which will reveal the
existing figure. Each digit can be adjusted using
the
Up
and
Down
push-buttons, and the
P
button
to move to the next digit. When the required
hysteresis has been entered, press
E
to return to
the alarm menu.
e.g. An indicator calibrated to display 0 to 10000,
with a high alarm set at 9000 and hysteresis of 200
will perform as follows:
High alarm will be activated when display
equals or exceeds 9000, but will not reset
until the display falls below 8800.
9.2.9 Alarm delay: dELA
This function enables activation of the alarm output
to be delayed for a fixed time following the alarm
condition occurring. The delay can be
programmed in 1 second increments up to 3600
seconds. If a delay is not required zero should be
entered. To adjust the delay select 'dELA' from the
alarm menu and press
P
which will reveal the
existing delay. Each digit of the delay can be
adjusted using the
Up
and
Down
push-buttons,
and the
P
button to move to the next digit. When
the required delay has been entered, press
E
to
return to the alarm menu.
9.2.10 Alarm silence time: SIL
This function is primarily intended for use in small
installations where the alarm output directly
operates an annunciator such as a sounder.
When the alarm silence time is set to any figure
other than zero, the
P
push-button becomes an
alarm accept button. After an alarm has occurred,
operating the
P
button will cause the alarm output
to revert to the non-alarm condition for the
programmed alarm silence time The display will
continue to indicate an alarm after it has been
accepted and silenced.
The alarm silence time may be adjusted between 0
and 3600 seconds in 1 second increments.
To adjust the alarm silence time select 'SIL' from
the alarm menu and press
P
which will reveal the
existing time. Each digit can be adjusted using the
Up
and
Down
push-buttons, and the
P
button to
move to the next digit. When the required time has
been entered press
E
to return to the alarm menu.
9.2.11 Access Setpoint: AcSP
This function controls a separate menu which
provides direct access to the alarm setpoints when
the indicator is in the display mode. See section
9.2.12 for a full description. An operator may
therefore adjust the alarm setpoints without having
access to the programme and alarm menus.
Further protection is provided by a separate
security code.
This direct access menu is enabled and a separate
security code entered from the 'AcSP' function in
the programme menu as shown in Fig 11. To
change the menu parameters select 'AcSP' from
the programme menu and press
P
which will
display the enable prompt 'EnbL'. Press
P
again to
reveal if the direct access menu is 'On' or 'OFF'.
The
Up
or
Down
buttons will toggle the display
between the two conditions.
If 'OFF' is selected, the operator will not have
access to the setpoints from the display mode.
Return to the 'AcSP' prompt in the main menu by
pressing
E
twice.
If 'On' is selected, the operator will have direct
access to the alarm setpoints from the display
mode via a separate optional security code. To
define the four digit numerical code press
P
to
return to the 'Enbl' prompt followed by the
Up
or
Down
button to select the access code prompt
'AcCd'. Pressing
P
will reveal the current security
code. Each digit of the code may be changed by
operating the
Up
and
Down
push-buttons, and the
P
button to move to the next digit. When the
required code has been entered, press
E
twice to
return to the 'AcSP' prompt in the Programme
Menu.
Code 0000 will disable the security code allowing
direct access to the setpoints by pressing the
P
and
Up
buttons simultaneously.
New instruments with alarms are supplied with this
function disabled and the security code set to 0000
