Syncro AS Panel – remote power connections
The Syncro AS control panel includes an on-board 3 Amp EN54-4 approved power supply unit.
Supplied via a transformer and bridge rectifier fitted in the rear of the panel enclosure, the on-board power supply provides a 28 volt d.c. output that is used to power the panel, drive the powered outputs and also to maintain the standby battery.
Of the 3 Amps provided by the power supply unit, 2.3A are available to drive the panel and output circuit loads and the remaining 700mA is used to charge and maintain the batteries in accordance with EN54-4 requirements.
The maximum batteries supported by the control panel power supply are 9Ah (high capacity batteries), which are typically sufficient to provide 24 hours standby and 30 minutes alarm.
NOTE: This also applies to the “larger M3 enclosure” variant of the Syncro AS panel, as the same power supply is used.
In situations where longer standby times are required, or where a standing load is taken from the Aux24 volt output, larger capacity batteries are required.
It is not recommended to connect larger capacity batteries to the standard power supply battery leads, because the 700mA charge current is not sufficient to re-charge the batteries within the times specified by EN54-4 and local codes of practice.
In addition, there is insufficient space within the panel enclosure to support larger batteries.
In such situations, the Remote PSU terminals on the Syncro AS panel are used to allow the connection of a remote EN54-4 approved power supply unit.
Two sets of terminals are provided, which allows two transmission paths to be provided between the power supply and panel in accordance with EN54-4 clause 6.6 requirements. These terminals are diode blocked, to prevent a short on one input affecting the other input.
A power fault input is also provided, to give a common power fault indication for the remote power supply. A power fault is given when 0V is applied to the PF terminal. This 0V must originate from the Syncro AS 0V terminal and is routed through volt free fault relay contacts on the power supply, rather than using the 0V from the remote power supply.
When using the remote power supply, it is necessary to continue using the internal on-board supply, as there is no provision to disable the on-board mains fail and battery monitoring hardware.
To ensure reliable operation, the internal and external power supplies must be powered from the same mains spur, such that a fault will cause both to switch to their standby batteries at the same time.
The battery capacity is the sum of the external power supply batteries capacity and the 7Ah (or 9Ah high capacity) batteries within the Syncro AS enclosure.
The protection diodes at the Remote PSU terminals prevent the panel batteries from attempting to feed the remote power supply unit.
For further advice on any of the items in this bulletin, please contact the Technical Support team on +44 (0)1322 222121 or by e-mail using firstname.lastname@example.org