23
Fig 10 Equivalent circuit of each alarm output
Note:
Because of the series protection diode
some test meters may not detect a
closed alarm contact.
Fig 11 Typical alarm application
8.2.2 Programming and adjustment
When a BA554D is supplied with alarms the
main programme menu is extended as shown in
Fig 12. The two alarm functions appear
between the 'C--P' and the 'SCALE-t' functions,
and each alarm may be programmed as a rate
or a total alarm.
For simplicity Fig 12 only shows the
programmable functions on the rate option of
alarm AL1. Alarm 2 and the total options are
identical except that the total alarms do not have
hysteresis.The following table summarises each
of the alarm programme functions and includes
a cross reference to more detailed information.
Again only the functions on alarm AL1 are listed.
Summary of programmable alarm functions
Display Description of function
'EnbL'
Alarm enable
Enables or disables the alarm
function without changing the alarm
parameters.
See section 8.2.3
'tYPE'
Type of alarm
Defines whether the alarm operates
on the rate or total display.
See section 8.2.4
'SPr1'
Alarm setpoint 1
or
Adjusts the alarm setpoint. The
'SPt1'
alarm is activated when the rate or
total display equals the setpoint.
See section 8.2.5
'HI.LO'
Alarm function
Defines whether the alarm has a
high or low function
See section 8.2.6
'no.nc'
Normally open or normally closed
output
Determines whether the single pole
alarm output is open or closed in the
non alarm condition.
See section 8.2.7
'HStr'
Hysteresis
Adjusts the alarm hysteresis. Only
available on rate alarms.
See section 8.2.8
'dELA'
Alarm delay
time
Adjusts the delay between the
display equalling the setpoint and the
alarm output being activated.
See section 8.2.9
'SIL'
Alarm silence time
Defines the time that the alarm
output remains in the non-alarm
condition following acceptance of an
alarm.
See section 8.2.10
'AcSP'
Access setpoint
Sub-menu which enables direct
access to the alarm setpoints from
the operating mode and defines a
separate security code.
See section 8.2.11
