Xylem 795 MJK Data Transmitter - Manual (Page 30)

30 M795GB0503
Data Transmitter 795
SW ver. 830434
16 Alarms
16.1 Operational or alarm signal
The digital inputs can be set to be either a
operational or alarm signals.
An operational signal defines a non-critical con-
dition, e.g. a signal that only need to be recorded
in the operational log. It would typically be a sig-
nal indicating whether a pump is running or not.
An alarm signal is a signal, which normally is not
active and only becomes active when critical con-
ditions occur, e.g. a thermal overload signal from
a pump. Furthermore, an alarm signal has me-
mory and reset, i.e. when the alarm signal
becomes no-active, the previous active condition
are remembered. This previous active condition
must be reset by the user before a new change
to active condition will be accepted as an alarm
signal.
For both types of signals are applied that both the
number of changes to active condition and the
period of time where the signal has been active
will be recorded in the alarm record.
16.2 Alarm calls
If 'Call on alarm' is selected, the Data Transmitter
will call all the numbers in the telephone list star-
ting with the first entry. Proceeding to the next
number in the list will take place after a preset
period of time -'Pause between calls'. See also
section 13.
If a call is made to a modem on a SCADA main
station, it will be the main station's task to reset
the alarm and stop the dialout routine. If call are
made to a pager or telephone, the dialout routine
is stopped by making a call to the Data Transmit-
ter. A tone will be heard in the handset. This will
not reset the alarms, but only stop the dialout
routine. See also section 15.3.1.
If another alarm occur during the dialout routine,
the dialout routine will continue, and the new
alarm will be reported in to the next number in the
telephone list.
Versions with radio modem transmit all alarms to
the main station (ID no. 0).
16.3 Reset of alarms
When an alarm signal becomes active, it will be
visible in menu F8 (see section 5.8).
Whenever a digital alarm signal becomes active,
the alarm will be present in menu F8.1. This menu
will show the alarm type and start time together
with a flashing symbol ' '. The symbol will flash
as long as the alarm has not been reset, and the
symbol will appear solid when the alarm has been
reset but still active.
The symbol disappear when the alarm has been
reset and the alarm signal is inactive. When the
symbol disappear, the stop time for the alarm is
displayed instead of the start time.
In order to reset an alarm from the front panel of
MJK Data Transmitter 795, the menu F8 must be
shown. Then use the arrow keys to select the
alarm to be reset. Reset the selected alarm by
pressing ENTER. The symbol ' ' will then appear
solid if the alarm signal is still active or disappear,
if the alarm signal is no longer active. An alarm
can also be reset from a SCADA system.
An alarm signal must have been reset and
change from non-active to active condition in
order to be visible in the alarm list again. This
means that if you do not want to receive the
same alarm call several times on the SCADA sta-
tion, the alarm should not be reset. The Data
Transmitter will then stop further alarm calls
concerning that particular alarm even if the alarm
signal change from non-active to active condition.
15.3.1 Automatic reset of alarms
If an alarm has not been reset, and another 9
alarms occur, meaning that the not yet reset
alarm becomes no. 10 and therefore no longer
will be visible in the alarm list, the alarm will be
reset automatically, if the function 'Automatic
reset of alarms' has been activated. See also
section 6.11.