Design criteria

Design objective

1. Real-time online monitoring of the temperature information of each intelligent warehouse location to provide security for the safe operation of the warehouse;

2. Provide temperature anomaly points for each storage location;

3. Clearly indicate the temperature anomaly location, and upload the warehouse location signal to the stacker or fire alarm system for rapid processing;

Project overview

Intelligent three-dimensional storage as a modern large-scale storage place, the safe operation of each warehouse in the warehouse requires real-time online monitoring of the temperature and fire situation of the warehouse, and temperature sensing optical cables are laid under each warehouse. Through real-time temperature monitoring, the temperature anomaly of the warehouse can be accurately located and warned in advance, providing effective guarantee for the safe operation of the warehouse.

Supporting scheme

Distributed optical fiber temperature measurement system is an intrinsically safe, distributed measurement, suitable for large space places, linear objects and dangerous places of the ideal monitoring system, the system can detect the temperature change of the warehouse to determine and locate the fault location and provide predictive warning. This optical fiber temperature measurement system is composed of optical fiber detection system controller (optical fiber temperature measurement host), detection cable, related software and other necessary accessories.

Equipment selection

According to the scale of the project, the number of sites monitored by the project, the location of the host and the design requirements of the latest national standard "Code for Design of Automatic Fire Alarm" GB50116-2013, as well as the analysis of the installation and construction of the site, the temperature detection of the single extension location is carried out according to the length of the optical fiber of 4 to 5 meters (the specific number is determined according to the size of the storage site). Distributed fiber-optic fire detection for temperature and fire monitoring of warehouse Spaces.

The optical fiber temperature measuring host can operate separately and display the temperature directly using the display, or upload the alarm signal to the stacker system in real time through the Ethernet. Once the battery temperature in the upper tray of a storage location exceeds the set temperature, the alarm signal will be transmitted out and the abnormal goods will be processed. At the same time, the data can be uploaded to the fire alarm host through the relay, and the fire alarm host can upload to the centralized control system workstation in the monitoring room.

Construction scheme

Laying scheme

The cable mounting plate is placed on the top of the corresponding cargo space, and the hook is designed on the mounting plate according to the size requirements of the above drawings. The hook is formed by stamping at a time. The size drawing and hook design drawing are as follows:

Figure: Schematic diagram of space size of single extension warehouse

Figure: Hook size diagram

Fiber laying

Temperature optical fiber is not only the carrier of the signal, but also the temperature sensor, the quality of the installation is directly related to the accuracy of the measurement, so special attention should be paid to the installation process in the construction. The optical cable installation diagram is as follows:

Figure: Schematic diagram of optical fiber laying in single extension position

The optical cable consumption of a single storage location in normal temperature storage and high temperature storage is about 3.8 meters;

The temperature sensing cable is arranged in the card slot of the mounting frame at the bottom of the cargo tray with a mesh, and the card is fixed by pressing the card.

Figure: Schematic diagram of laying of temperature measuring cable for single-layer shelf

When laying temperature sensing optical cable, follow the principle of laying the next layer after the completion of laying one layer to maximize the construction efficiency of optical cable. The temperature sensing cable is laid from the 1# compartment until the last compartment is laid.

The temperature sensing optical cable is laid in S-shape on the mounting plate above the cargo compartment of each layer, first down and then up. The beginning end of the temperature sensing cable is connected to one of the channels of the temperature measuring host, the middle is connected to the cable of about 150 meters, and the tail is reserved for 50 meters of cable, and it is raked into a small ring for protection. The quantity of goods in each reservoir area is as follows:

Figure: Schematic diagram of laying single row shelf temperature measuring cable

Temperature measurement system site layout

The temperature sensing cable is fused with the tail fiber, and the welding part is protected by the cable connection box. The temperature sensing optical cable is led out from the measuring host and laid above each warehouse. A 3.8m temperature sensing optical fiber is laid in one warehouse. The temperature sensing optical fiber is fixed at the top of the warehouse with optical fiber fixings.

The temperature measuring host is connected with an external industrial computer, and the client software is installed in the industrial computer, which is mainly used for instrument parameter setting and management, and displays the temperature and alarm information of each storage location. The host can use relay, TCP/IP, and other different ways to carry out the alarm signal last time, if the alarm can be processed in time.

Optical fiber temperature measuring host technical specifications (with national fire 3C certification)

Ø Type No. : DF-DTS500;

Ø 

Origin: Ningbo, China;

Ø Maximum detection distance of single channel: 10 km;

Ø Applicable fiber type: 62.5/125;

Ø Number of channels: 4;

Ø Connection with optical fiber: FC/APC;

Ø Measurement time: ≤5 seconds/channel;

Ø Sampling interval: 0.5 m;

Positioning accuracy: 1 m;

Ø Temperature measurement accuracy: ±1℃;

Ø Temperature resolution: ±0.1℃;

Ø Temperature range of the host: -273℃ ~ 700℃ (according to the selected optical cable);

Ø Relay: 8 ways (external relay box, can be expanded countless ways);

Ø Communication interface: RJ45, RS232/RS485, USB;

Communication protocols: TCP/IP, OPC, MODBUS, etc.

Ø Alarm mode: constant temperature, differential temperature (temperature rise rate) and temperature difference alarm (set by software);

Ø Maximum alarm zone: 300 /km, each area arbitrary set length and temperature alarm line, fiber damage can automatically detect and locate the damaged point, and detection cable collection signal will not be lost;

The laser safety level of the system meets: IEC60825-1(2007) Class 1, reaching the most advanced laser level, completely harmless to human eyes;

Ø The product meets the requirements of electromagnetic compatibility

Ø Operating environment: -10℃ ~ 50℃;

Storage temperature: -20℃ ~ +60℃;

Ø Relative humidity: <95%RH (no condensation);

Product size: 482mm(W)*89mm (H)* 461mm (D)

Ø Net weight: 9kg

Ø Installation mode: 19" rack type;

Temperature sensing cable

Sensing fiber Multi-mode 62.5/125 (core/cladding/acrylic coating) Circular gradient refraction multi-mode fiber, fiber loss: ≤3.0dB/km (wavelength 850nm), 0.7dB/km (wavelength 1300nm), cable built-in Kevlar fiber, stainless steel hose, stainless steel woven net, covered with anti-static flame retardant PVC outer sheath, with good flame retardant and anti-static characteristics. This sensor is a non-electrical product, intrinsically safe, no power supply, no heat source, no static electricity.

Ø Optical fiber model: DF-GTH;

Ø Fiber type：          62.5/125

Ø Fiber core number：          Single core

Ø Insulation sheath diameter: 0.9mm

Ø Metal sheath material: with 2.1mm stainless steel thread hose armor sheath. The sheath makes it easier to operate during installation and improves mechanical stability;

Ø Outer sheath material: with 3.0mm anti-static flame-retardant low-smoke halogen-free material as the outer sheath, it has high thermal radiation sensitivity, good waterproof and moisture-proof performance, and can avoid static electricity caused by friction of optical cable, fully meeting the needs of explosion prevention, engineering installation and long-term operation;

Ø Minimum bending radius: less than 60mm;

Ø Protection grade: ≥IP67;

Ø Tensile strength: maximum 300N during installation; Maximum 500N during use;

Ø Compressive strength: maximum 2000N/10cm during installation; Maximum 1000N/10cm during use;

Ø Linear grinding pressure: 300N/cm causes deformation of ~0.3mm;

Ø Detection temperature: -30℃ to +90℃ (long-term), 120℃ (>120 hours);

Ø Cable working life: more than 30 years;

Ø Anti-impact, repeated bending, twisting, bending, winding, water seepage performance are in line with IEC794-1 standards. Optical cable is inherently safe, with anti-electromagnetic interference, anti-mechanical impact, anti-corrosion, high voltage insulation strength characteristics.

Alarm mode

Optical fiber temperature measurement system 24 hours online monitoring, in order to obtain more high-precision temperature data, every 5 seconds to collect 1 channel temperature data, compared with the historical data and set the threshold, if the temperature abnormal change is found, indicating that the ambient temperature of the cable has changed, if the change range reaches the system preset alarm threshold, the system automatically provides alarm prompts. And upload the alarm information to the stacker system or fire alarm control system in real time. The system alarm has the following two types of alarm:

Constant temperature alarm

Fixed temperature alarm algorithm: set a fixed temperature alarm limit value T, and then check each temperature point, whether to reach or exceed this limit value T, if reached or exceeded the alarm.

Setting and checking mode: The limit value is set in each zone, and according to the fixed temperature limit value of each zone, whether the temperature value of the zone exceeds the limit value is determined, the zone will alarm; It is necessary to traverse all the temperature points to which the partition belongs, and the last alarm value is the temperature of the highest temperature point.

Differential temperature alarm

Temperature rise alarm algorithm: calculate the temperature change per minute at each temperature measuring point on the cable, and the temperature rise will change dynamically with the cable temperature.

Setting and checking mode: similar to the setting and checking mode of constant temperature alarm.

Partial scene photos