Nexus 21 A1557 technical specifications Number Loops

3.0Engineer’s Functions

A number of engineering functions are provided by the control unit in order to allow the system to be configured specifically to accommodate site requirements. Further functions are provided to assist in commissioning and servicing the finished fire detection system.

There are three separate codes for access to the three engineer function levels. When the codes have been entered, the user is guided through the sequence of operations, for the chosen function, by text displayed on the LCD.

Prior to entering the engineers function menus, it is necessary to check that the panel is configured to the correct quantity of loops, open the display door and locate the 4 position DIL switch marked SW1. The switch settings are tabulated below:

SW1-3	SW1-2	SW1-1	NUMBER LOOPS
OFF	OFF	OFF	1 LOOP
OFF	OFF	ON	2 LOOP
OFF	ON	OFF	3 LOOP
OFF	ON	ON	4 LOOP
ON	OFF	OFF	5 LOOP
ON	OFF	ON	6 LOOP
ON	ON	OFF	7 LOOP
ON	ON	ON	8 LOOP

SW1-4 should be in the OFF position if the panel is to operate as a standard system. If the panel is to operate as part of a network system then SW1-4 should be in the ON position.

Notes: The time/date function is now backed up by an internal lithium “coin cell”. This battery is non rechargeable but at 70 mAh, will support the clock in conditions of total power failure, for 10 years. The replacement of this battery is intended to be carried out by service engineers only. The part number is CR1620.

The download lead is a standard “null-modem” RS232 lead with 9 pin D type connectors. This can be supplied by CEL or obtained direct from Maplins - catalogue ref VD76H. New lead connections below:

Panel end		PC end
Pin	Link	Pin	Link
2		3
3		2
7		8
8		7
5		5
1		4
6
4		1
		6
9		9

The “Cherry” keyboard in current use can be connected directly to the motherboard via J14 5 pin Din socket without use of the converter lead.

Document Ref: Nex8inst.doc/Rev0 09.07.00 Page 9 of 30 Originator MC Checked by AC__