User Manual 990-9178A
DC MX06 40A Shelf Page 13 of 44 18th FEB 02

2.4 Alarms

2.4.1 Available Alarms
To monitor the system status a selection of alarm outputs are available. Dependant upon the rectifiers
fitted either 4 front panel LED’s or a single LED give visual notification of a system fault. There is also a
range of open collector transistor alarm outputs, which can be accessed at the rear of the shelf or on a
front panel connector (selected models). Finally there are 2 sets of relay contacts that can be configured to
represent 1 or more alarms selected by the user.
Below is a list of the available alarms along with their function and pin number.
Note/ Alarms marked with a * are not available if system is fitted with single LED rectifiers.

Alarm / User

Outputs

Description Rear

Access

Front

Access

Bus Voltage Low System volts dropped to LVD set level +10%, LVD imminent SK14-2 SK4-25
* Fan Fail One or more of the Rectifier fans have stopped SK14-3 SK4-24
2+ Rectifiers Fail 2 or more rectifiers giving output less than 31Vdc SK14-4 SK4-5
Rectifier Fail 1 Rectifier giving output less than 31Vdc SK14-5 SK4-6
Distribution Trip 1 or more fuse blown or breaker tripped SK14-6 SK4-2
AC Fail 1 or more of the AC input feeds failed SK14-7 SK4-1
* Over Current 1 or more rectifiers in current limit state SK14-8 SK4-23
* Over Voltage 1 or more rectifiers tripped due to excessive o/p voltage
(interrupt AC input or remove rectifier and refit to reset)
SK14-9 SK4-22
* Over Temperature 1 or more rectifiers tripped due to excessive internal
temperatures (resets itself when cooled down)
SK14-10 SK4-21
Signal Common Use to reference all alarms to SK17-1 SK4-17
Current Share Use for paralleling purposes only SK17-3 SK4-16
Current Analogue Analogue voltage representing load current (1V = 5A ± 5%) SK17-4 SK4-19
5V Auxiliary Low current capability 5V supply for use with current limit
programming.
SK17-5 SK4-15
Major Failure ‘Minor’ relay contact (closed for alarm) SK18-1 SK4-11
“ “ ‘Minor’ relay contact (Common) SK18-2 SK4-10
“ “ ‘Minor’ relay contact (open for alarm) SK18-3 SK4-12
Minor Failure ‘Major’ relay contact (closed for alarm) SK18-4 SK4-8
“ “ ‘Major’ relay contact (Common) SK18-5 SK4-7
“ “ ‘Major’ relay contact (open for alarm) SK18-6 SK4-9
Warning! All alarm outputs other than the relay contacts are open collector transistors. Each output has a
max voltage rating of 60Vdc and a current sink capability of 20mA