Nexus 21 A1557 technical specifications Status To Printer

The keypad keys 1, 2 & 3 become control switches for the 3 control panel command bits. (Indicated by the numbers 123 under the CMD indicators).

Pressing key 1 causes command bit 1 to toggle between 0 and 1, key 2 for bit 2 and key 3 for bit 3.

The 3 command bits have different purposes depending upon the device type. In the case of smoke (ion and opt) and heat sensors, the command bit allocation is as follows:

1Turn on Remote LED

2Enter self test mode

3Turn on Sensor LED

Break glass units respond to bits 2 & 3 only.

For command functions of other devices, refer to relevant literature.

Typical control example:

When a command bit is sent to a device, after a short delay, the status confirmation - returned from the device - will be shown on the LCD. With the display as shown above, pressing key 3 turns on the sensor LED at device number 100. Pressing key 3 again turns it off.

WARNING: In the enabled condition the response of devices to the command codes will be relatively slow due to the fact that the control panel is polling all connected devices and command bits are required to be sent to the device twice.

When an ionisation sensor is tested, the display may briefly show an “ALERT” condition as the sensor output rises. Other sensors react more quickly and appear to reach FIRE condition immediately.

WARNING: If tests are carried out in the disabled mode, it is essential that the command bits for each device be returned to 000 before moving on to another device. Failure to observe this requirement will mean that, if a device has been left in the test mode, upon returning to normal operation a fire alarm condition will be raised.

The control panel does clear the command bits upon return to normal operating condition but the sensor devices respond too slowly and the control panel reads this as a fire alarm condition.

To exit from the status option, press the # key. This returns the control panel to normal operation.

5.8.2Status To Printer

The format of the printed status report is shown in the short example below: