XP95 - Addressable analogue detectors

The fire detectors series XP95, manufactured by the Apollo Fire Detectors Ltd., embody a next step in developing the addressable analogue detectors series 90. The uppermost international level of engineering, a high reliability, a discrete design, easy installation of the detector into its socket (practically no force is required) all these distinguish the detectors from the others available in the market. They have been tested under extreme conditions. The test results have proved excellent performance of the XP95 detectors.
The detectors are addressable, which means that a central unit may communicate with an individual detector.
The detectors are analogue, which denotes they measure the actual magnitude of a parameter such as a smoke concentration or temperature in a 99-grade-scale. Contrary to the conventional detectors, which either enable a fire alarm or not, the XP95, upon the conversion of the analogue signal into a digital one, send the latter to a central unit and it is where a process occurs to determine whether there is a reason to enable fire alarm. The XP95 series includes: ion-based detectors, optical detectors, manually operated alarm devices (in the break-the-glass design), and two types of heat detectors (one for fire detection in a standard temperature range; the other for a high temperature range).

Addressable analogue detectors series XP95

They are supported by alarm central units. One of these is the ANX95E produced by the Eltek, Norway.
The detectors are connected with a pair of wires, which is a means for supplying power and transmitting data between the detectors and central unit. The detector socket is also fitted with a ground terminal, it does not, however, have any effect upon the operation of the detector. The connecting terminals or the detector are not specifically polarised (which is the case with the short-circuit isolator, where the terminals plus and minus are defined). Compared to the detectors series 90, an extended transmission protocol is applied (baud rate is increased), thanks to which a more comprehensive flow of information between a central unit and the XP95 detectors is attained, whereby a downward compatibility occurs (an XP95 may replace a detector series 90).
The most important features are summarised below:

• an alarm flag is introduced. This flag along with the address is sent by the detector to a central unit at the point when an actual smoke concentration (or another parameter measured by the detector) has exceeded an alarm threshold (which equal to 55 units) and during the subsequent second upon the alarm condition the central unit would not check out the detector for the smoke concentration. By transmitting the alarm flag the detector provides important overriding information.
• a parity bit is applied which enables error detection
• two extra Type Flag bits are employed, whereby the number of recognisable devices rose to 32 off
• the data word length is extended from 7 to 8 bits, whereby the resolution of analogue data (smoke concentration, temperature) is improved. At the same time there is some space left for further extending the data word length up to 12 bits.

The detectors send values to a central units that are in a proportion to a specific parameter (smoke concentration, temperature) to be measured. The detectors are calibrated so that the alarm condition corresponds to a value equal to 55 units. In a fire central unit, however, dependent on specific local conditions, a fire alarm may be turned on at other values to be sent by the detector. When in a monitored room some processes are carried out which cause smoke, dust, elevated temperatures, then alarm levels may be increased. In hotel rooms, hospitals where ambient conditions are stable, alarm thresholds may be relatively lower. LEDs on the detector as well other indicating devices hooked up to it are activated after the detector has received an order from a fire central unit. Such an order occurs when the actual value sent in from the detector has been in excess of the relevant fire alarm threshold. With a short-circuit isolator the process is different. After short-circuit has been found and separation has been started, the yellow LED goes on since a signal from the short-circuit isolator is fed.

Ion-based smoke detector series XP95
Catalogue No. 55000-500

In this type of the detectors a low level ionising radiation is Americium 241 (since the actual radiation is extremely low, so there is no limitation as to the number of the detectors). Ions freed by radiation enable a current flowing in both measuring and a reference chambers. In case of fire, combustion products bond the ions, so the actual current within the measuring chamber is reduced (while the other chamber is tight and no smoke enters it). The measurement is carried out on an ongoing basis. A current differential between the chambers is captured and processed in an A/D converter. The resultant value in a digital format is fed to a central unit.

Optical smoke detector series XP95
Catalogue number 55000-600

With this type of the detector, every one second (or when demanded by a central unit) a LED sends a focused infrared light beam. It passes by a receiver without illuminating same. Once smoke appears, it disperses the beam and as a result, light reaches the receiver causing a current to flow. Once amplified, the signal is fed to an A/D converter, and the attained figure is sent to a central unit as the actual smoke concentration value. An original setting of 55 units across the detector corresponds to a smoke concentration that at a 1m distance absorbs 2.4% of light. At the same time is a standard alarm threshold.

Heat detector series XP95
Catalogue No. 55000-400 (standard temperatures)
Catalogue No. 55000-401 (high temperatures)

With this type of the detector, the temperature measurement is performed with the aid of one thermistor. The resistance of the latter changes with temperature. The measuring current across the thermistor is also affected. The measured current value (which is in a proportion to the temperature) is transformed to a figure by an A/D converter. Its characteristic is linear within a range of 25...90OC (the detector acts as a temperature gauge). In a fire alarm central unit an algorithm for computing the temperature increase rate, which leads to an accelerated fire alarm, should the temperature be soaring up.
At 25oC, the both types produce a value of 25 units. With the detectors for standard temperatures the output value increment is 1 unit per 1oC; it denotes that 55 units (alarm condition) is reached at 55oC. The high temperature detectors reveals another gradient of its working curve. It is 2.17oC per the output value unit, so a value equal to 55 units (alarm threshold) is reached at 90oC.

Short-circuit isolator
Catalogue No. 55000-700

The short-circuit isolator is to shut off a section of a line should it be shortciruited between two isolators or between terminals and the isolator. Once the short-circuit has been corrected, the affected section is automatically re-connected. Pursuant to the relevant regulations, every group od 32 detectors, every group od 10 manual alarm devices and in between manual alarm devices and detectors (irrespective of their number) should be protected against short-circuits by means of the said isolators.

 

Manual alarm device series XP95
Catalogue No. 55000-910 (for enclosed spaces)
Catalogue No. 55000-950 (hermetic design)

While operating normally, the device sends a value in excess of 15 units to a central unit. Once glass has been broken, fire alarm is enabled. At this point the device feeds an interruption flag and its address to the central unit which is to communicate that there are data, which are to be received by the central unit. Once a check on the actual output value level, the device sends a value of 64 units (i.e. the prescribed 55 units’ level is surpassed) to the central unit. In addressing the device, the 8-pole microswitches type DIP are used. The zero address corresponds to the all levels set to the ON position.

Socket for the XP95 detector with the XPERT card
Catalogue No. 45681-210

Addressing the detectors is done with the help of the XPERT card. In this solution the address of such a detector is specified by removing (or not) pins, whereby a mechanical address of the XPERT card is set. Then the card is inserted into the base of the detector. Upon mounting the detector in place, the pins push against switches, and thus the mechanical address is converted in an electronic address. Here replacement of the detector does not necessitate setting the address anew, which expedites both mounting and commissioning activities, precludes errors due to maintenance and servicing of a building.

About Apollo

The Apollo company belongs to the largest manufacturers of fire detectors. In 1999 its production reached more than 2,300,000 off which were sold. Numerous awards and prizes attained by Apollo confirm a high quality and a reliability of the equipment it manufactures. The Apollo products have been approved to the UL., LPC and LRS, VdS and GL, and certified by the CNBOP, Józefów, Poland.
The Fire Stop Sp. z o.o. is a general distributor of the products of the Apollo Detectors Ltd.
All the names and markings of the equipment are registered trade marks. It is the Fire Stop Sp. z o.o. which has any and all the rights to the products and to their approvals within Poland.

Reference list of premises and establishments where analogue-addressable systems are employed