Digital Type Linear Heat Detectors

Compared with other kinds of detectors. Digital Linear Heat Detector provides a very-early alarm detecting function to the protected environment. The detector can be known as an intelligent “switch” type detector. The polymers between the two conduc-tors will break down at specific fixed temperature allowing the conductors contact, the shot circuit will intimate the alarm. The detector has a continuous sensitivity. The sensitivity of linear heat detector will not be influenced by the environment temperature changing and the length of detection cable using. It does not need to be adjusted and compensation. The detector can transfer both alarm and fault signals to control panels normally with DC24V.

Linear Heat Detection Cable

1. Classsification

Conventional Type

This type of Linear heat detection cable is the most widely indoor used with strong stability.


CR/OD Type

CR/OD Type not only has good UV resistance and good weather resistance, strongly recommended for outdoor using even under bad weather conditions, but also with high performance of acid resistant, alkali-resistant, salt spray resistant.


Explosion Proof Type

Explosion Proof Type. Two main application environments: harsh EMI environment and explosive hazardous environment. The outer jacket of this type is protected by woven metal mesh with good performance of anti ­EMI and eliminating the surface static of the Linear heat detection cable. We can use this type Linear heat detection cable in explosive hazardous environment with safety barrier. During the installation, please make grounding connection of the woven metal mesh. Used in harsh EMI environment, single end grounding connection or double ends grounding connection should be specified after analysis of the interference sources.

2. Structure

Intertwisting two rigid metallic conductors which are covered by NTC heat sensitive material, with insulative bandage and outer jacket, here comes the Digital Type LHD Cable of P.T.S., and the different models depend on the variety of materials of outer jackets to meet different special environments. 

3. Features and benefits

• Industrial safety design
• Electrical interface with low power consumptioo design
• Real-time monitoring
• Fast response time
• No alarm temperature compensation needed
• Compatible to any kind fire alarm system
• Alarm temperatures: 68°C, 88°C, 105°C, 138°C&l80°C. 

Control Unit And EOL Box

Control Unit

Control Unit all digital type Linear Heat Detection Cable. (the Explosion-proof tank and Safety barrier med to come with Control Unit for EP type). It is a digital type Linear Heat Detection Cable with comparatively simple output signal, the Control Unit and End of Line (EOL) Box are easy to install and operate.

End of Line (EOL Box)

EOL Box for digital Linear Heat Detection Cable.

1. Technical parameters

• Operating Voltage: 24VDC
• Allowed Voltage Range: 16VDC-26VDC

• Operating Current :Standby Current: ≤ 2mA , Fire Current: ≤35mA , Fault Current: ≤25mA
• Operating Environment :Temperature: -45°C-+60°C Relative humidity: 95%
• For Indoor use only• Application Length: no loger than 500m
• Dimensions:90mmx85mmx52mm(LxWxH)

1. Technical parameters

• Operating Voltage: No Electronics
• Operating Environment: Temperature: -45°C-+60°C Relative humidity: 95% 

• For Indoor use only
• Dimensions: 90mmx85mmx52mm (LxWxH)
• Notice: “Fire Test” “Fault Test”

push battons are for testing use only.

2. Cable connecting instruction

l)Connecting drawing 


• Cl C2: with sensor cable, non-polarized connection
• A, B: with DC24V power, non-polarized connection
• EOL RESISTOR: EOL RESISTOR (conforming to input module)
• COM NO: fire alarm output (resistance value in fire alarm<S0Q)

2. Cable connecting instruction

l)Connecting Drawing 

• Cl C2: with sensor cable, non-polarized connection

Control Unit with Locator

It is a controlling device to monitor the temperature change of sensor cable and connected to mainframe of intelligent fire alarming control panel. It performs continuous monitoring over fire alarm and open circuit of monitored area as well as distance from fire alarm position. These alarming signals are shown on the LCD and indicators of this type control panel. Since fire alarm has locking function. Control Unit with Locator must be disconnected to power and reset after ALARM. While fault function could automatically reset. it means that after the clearing fault, the fault signal of this type control panel is automatically cleared.

1. Features

• Plastic shell: chemical resistance,aging resistance and impact resistance
• IP rating: IP66 For Indoor use only
• With LCD, various alarming information could be shown
• The detector has high ability of interruption resistance adopting fine grounding measurement, isolation test and software interruption resistance technique. It is able to apply in places with high electromagnetic field interruption. 

2. Technical parameters

• Detector Type: Linear heat detector digital series
• Operating Voltage: DC24V
• Allowed Voltage Range: 16VDC-28VDC
• Standby Current≤60mA
• Alarm Current≤80mA
• Alarming Reset: Disconnection reset
• Status Indication: Stable power supply: Normal operation: Green indicator constantly lights.
Fixed temperature fire alarm: Red indicator constantly lights Fault:Yellow indicator constantly lights 
• Operating Environment: Temperature: -10C-+50C Relative humidity≤95%, no condensation
• Positioning Accuracy: <±Sm(under 25C environment)
• Application Length: No longer than 500m
• Outer Shell Protection Class: IP66

3. Cable connecting instruction

Dual Temperature Linear Heat Detector Cable

Dual Temperature Linear heat detection cable is a type with higher-performance of dual temperature alarms. So called “Dual Temperature Alarm” means that the Detector has two alarm temperatures . Level I is pre-alarm (lower rated temperature), Level II is confirmed fire alarm (higher rated temperature).

Dual Temperature Linear heat detection cable is comprised of three steel conductors each individually insulated with a unique heat sensitive polymer. The insulated conductors are twisted  together to impose a spring pressure between them, then wrapped with a protective tape and furnish with an outer jacket, as shown below:

The Detection Cable is capable of initiating separate pre-alarm and alarm signals once each of its rated activation temperatures is reached. At each of the rated temperatures, the heat sensitive polymer insulation yields to the pressure upon it, permitting the inner conductors to move into contact with each other thereby initiating the appropriate pre-alarm or alarm signal. This action takes place at the first heated point anywhere along the Detector’s length. It does not require that a specific length be heated in order to initiate an alarm nor is system calibration necessary to compensate for changes in the installed ambient temperature. Compensating adjustments are not required.

1. Product Descrption

2. Features

• Dual temperature alarm,Level I is pre-alarm, Level 11 is fire alarm;
• Confirmed temperature initiation for sprinkler release and extinguishing system;
• Lower false alarm rate than single alarm temperature detector;
• Withstands a wide range of environmental conditions;
• Compatible with other initiation devices on the same circuit;
• Easy to install and maintain.

3. lnstruction about the advantages

Linear Heat Detector, no matter digital type or analog type has false alarm rate due to improper use or other external factors, even the rate is extremely low, it may take our consumers in trouble in applications. We get the results shown as below after the research about causes of false alarm:

Linear Heat Detector, no matter digital type or analog type has false alarm rate due to improper use or other external factors, even the rate is extremely low, it may take our consumers in trouble in applications. We get the results shown as below after the research about causes of false alarm:

Dual Temperature Linear Heat Detector is theoretically designed to avoid false alarm or reduce the false alarm rate. As instructed above, this model has two alarm levels: Level I pre-alarm (lower rated temperature) and Level Il fire alarm (higher rated temperature) , in normal fire alarm signaling procedure, the pre-alarm comes first, then the fire alarm initiates consequentially, the time interval between two alarms can be nearly “O”
We consider it as false alarm signal instead of fire alarm signal in the situation which is not in accordance with normal fire alarm procedure, as shown below:

• Level II (higher rated temperature) alarms first;
• Level II fails to alarm long time after Level I (lower rated temperature) .

Thus, the detector can both reduce the false alarm rate and initiate pre-alarm and alarm signal. Moreover, Dual Temperature Linear Heat Detector has another feature of providing the consumer with convenience, the Detector can be connected to Fire Control System to initiate extinguishing systems directly, but the single alarm detector cannot theoretically, which only can confirm the fire alarm artificially or by auxiliary.

4. Matters needing attention

Dual Temperature Linear Heat Detector is a line coverage and heat sensitive detector. The Detector must be installed in continuous runs without taps or branches, at the ceiling level or on the side walls to protect areas in buildings (protection area ). Please refer to other details about installation and applications of the Detector.