25
The maximum equivalent capacitance and
inductance of each BA338C alarm output is:
C
= 40nF
L
= 30µH
To determine the maximum permissible cable
parameters, the equivalent alarm output
parameters must be subtracted from the maximum
cable capacitance and inductance specified by the
system certificate of the circuit connected to each
alarm.
Fig 12 Typical alarm application
9.3.3 Programming and adjustment
When a BA338C is supplied with alarms the main
programme menu is extended as shown in Fig 13.
The two alarm functions appear between the 'LOC-
rSEt' and the 'CLr.Gtot' functions, and each alarm
may be programmed as a rate or a total alarm.
For simplicity Fig 13 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 9.3.4
'tYPE'
Type of alarm
Defines whether the alarm operates on
the rate or total display.
See section 9.3.5
'SPr1'
Alarm setpoint 1
or
Adjusts the alarm setpoint. The
‘SPt1’
alarm is activated when the rate or
total display equals the setpoint.
Note:
‘SPr1’ is displayed for a rate
alarm and ‘SPt1’ for a total alarm.
See section 9.3.6
'HI.LO'
Alarm function
Defines whether the alarm has a high
or low function
See section 9.3.7
'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 9.3.8
'HStr'
Hysteresis
Adjusts the alarm hysteresis. Only
available on rate alarms.
See section 9.3.9
'dELA'
Alarm delay
time
Adjusts the delay between the display
equalling the setpoint and the alarm
output being activated.
See section 9.3.10
'SIL'
Alarm silence time
Defines the time that the alarm output
remains in the non-alarm condition
following acceptance of an alarm.
See section 9.3.11
'AcSP'
Access setpoint
Sub-menu that enables direct access to
the alarm setpoints from the display
mode and defines a separate security
code.
See section 9.3.12
