Nexus 21 A1557 technical specifications Ii Other Relevant Documentation

NOTES:

1.We strongly recommend the use of the Battery and Loop calculator for assessing the correct size of the standby batteries and correct loop function in all conditions.

2.Quiescent current is stated assuming mains failure conditions, therefore the general fault LED will be illuminated and the fault buzzer will sound.

3.The total current drawn by both alarm circuits operating must not exceed 2 Amps.

4.The total DC auxiliary current drawn must not the values stated in the Technical Specification. The power supply current limiting will operate if ratings are exceeded.

5.The battery charger employed is the constant voltage type and the current will be dependent upon the state of charge of the battery.

6.Alarm line monitoring operates using polarity reversal. All alarm sounders and/or visual alarms must be made polarity sensitive for line monitoring to operate correctly.

7.Repeater data output is available at terminals in the control panel. Two cores are required for the connection of repeater panels. The maximum cable length between the control unit and any repeater unit is 2000 metres. The cable must be suitable for RS485 data such as Belden 8132 or equivalent. If power is provided from the control unit, 2 additional cores are required.

8.The control panel provides an RS485 multiplex data link for driving additional output devices such as zonal relays, alarms, mimic indicators etc. The output functions are programmable at site level.

9.The number of sensor devices may need to be reduced due to the power requirements of the devices themselves. Fire sensors, heat smoke, call points etc. may be fitted in any combination up to the maximum (126) addressing capability of the protocol. Zone monitors in particular require a higher operating voltage and also draw significantly more current from the control unit; reference to the system design manual is necessary if zone monitors are to be used on the loop.

10.If any devices which contain an inductive coil (relays etc.) are connected to the panel, these should be suppressed by connecting a diode across the positive and negative connections of the coil.

iiOther Relevant Documentation

Sales Literature

Nexus 1-8 Loop Application Guide

Nexus 1-8 Loop User Instructions

Nexus Repeater Documentation

A1535 8 Way Relay Board Documentation

A1536 8 Way Alarm Board Documentation

PC-Based Software Programming Guide

Wiring Recommendations

Battery and loop Calculation Software