20
9.2.7 Alarm output status: no.nc
This function allows the alarm output to be open or
closed in the alarm condition. When deciding
which is required, care must be taken to ensure
that the alarm output is fail safe. See Fig 8.
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.
