FAULT DETECTIONS
PAGE 9
AMPERES AX3700
5
6
4
3
2
1
BUZZER
AMP/LINE
ALERT
FAULT
CHANGEOVER
AMP. NUMBER
FAULT
NORMAL
S/BY
POWER
ON / OFF
PILOT TONE ACTIVE
HOW IT WORKS
Although in principle most auto fault changeover works similarly in detecting faulty amplifiers, you may find
some difference in how AX3700 operates. AX3700 sends out Pilot Tone of 20 KHz at intervals and shift from
channel to channel. This reduces strain at the amplifiers where continuous loading is avoided. Though some
slight delay may occur during the detection period, this shall be beneficial in the long run. The maximum
fault detection window shall be around 25 seconds, which is acceptable in most cases.
Whenever Pilot Tone is active, PT ACTIVE LED shall lit, indicating that the unit is sending out 20KHz
signals to individual channels
PT ACTIVE
LED
CH.NORMAL
LED
CH.
TAKEOVER
LED
CH.FAULT
LED
BUZZER
SWITCH
AX3700 checks the returning PT signal from the output of amplifiers. A minimum 50V line rms is required
for detection. Failing in detecting the returning signal shall render the channel faulty. Thereby it is
recommended that the output of the amplifiers be set to 3/4 turn. AX3700 works even without the presence
of audio signal.
EFFECTIVE DETECTION LEVEL
INDICATIONS
Every faulty channel shall be indicated by CH FAULT LED. Unused channel which is not switched off shall
also be regarded as faulty channel. Thereby when there is any unused channel, switch it to OFF to prevent
false alarm.
Only a single takeover is allowed to prevent overloading of standby unit. Preference shall be given to unit
with higher number for takeover. ie. When channel 2 and 6 is faulty, channel 6 shall be allowed for
takeover. For cascading mode, please refer to section " Cascading AX3700 ".
Channel being takeover shall be indicated by CH.TAKEOVER LED. In the same time, buzzer shall be
activated and this can be silenced by the BUZZER SWITCH.
A closed contact shall also be established, with the port provided at the rear of the panel. This can be linked
to external sounder or mimic panel for indication.
RS485 port shall be available in future for activity monitoring.
