Industrial Ethernet switches and commercial switches are basically the same in data exchange functions, but in terms of design and the selection of components, the strength and suitability of products can better meet the needs of industrial sites.
In addition, the performance of the module expansion is more flexible than commercial switches: there are a variety of optical and electrical ports available for selection. It meets the needs of industrial sites in material selection, product strength, suitability and real-time, interoperability, reliability, anti-interference and intrinsic safety.
Industrial-grade design is generally designed to meet: industrial wide temperature design, 4 electromagnetic compatibility design, redundant AC and DC power input. In addition PCB board generally do "three defenses" processing.
Why should industrial sites use the right industrial Ethernet switches instead of cheap commercial switches? From the following aspects, we can determine the necessity of selecting industrial Ethernet switches in the industrial field.
1, due to the uncertainty <br> <br> a MAC layer protocol is Ethernet CSMA / CD, the protocol on the network such that there is a conflict, particularly when the network load is too large, more pronounced. For an industrial network, if there are a lot of conflicts, it is necessary to retransmit the data several times, so that the uncertainty of the inter-network communication increases greatly. This kind of uncertainty from one place to another in an industrial control network will inevitably bring about a reduction in the control performance of the system.
2, real-time <br> <br> in industrial control systems, real-time can be defined as a system testability of an event of reaction time. That is, after an incident occurs, the system must respond within a time frame that can be accurately predicted. However, the real-time requirements for data transmission in the industry are very strict, and often the data update is completed within several tens of ms. And because of the CSMA/CD mechanism that exists in Ethernet, when there is a conflict, you have to retransmit the data, and you can try at most 16 times. It is clear that this mechanism for resolving conflicts is at the expense of time. And once there is a drop, even if it is just a few seconds, it may cause the entire production to stop or even equipment, personal safety accidents.
3, the reliability of Ethernet <br> <br> Since early in the design, not the application from the industrial network. When it is applied to an industrial site, in the face of adverse conditions, severe line-to-line interference, etc., these will inevitably cause its reliability to decrease. Industrial networks must have good reliability, recoverability, and maintainability in a production environment. That is, to ensure that any component in a network system fails, it will not cause crashes and crashes in applications, operating systems, and even network systems.
Industrial Ethernet switches take into account the complexities of the industrial field when designing, so that they can adapt to the industrial environment and play the role of the switch.
The difference between IE switches and common switches is mainly reflected in their functions and performance.
The environment of the industrial site is worse than the ordinary environment. At least in vibration, humidity, and temperature, it must be inferior to the normal environment. The general switch is not designed to withstand the various situations that occur in the industrial environment. The ordinary switch cannot be long. Time works in such a hostile environment. It is often prone to failures and increases maintenance costs. It is generally not recommended to use commercial switches in an industrial environment. In order to enable the switch to be used in such harsh environments, the production can be adapted to Environmental switch, industrial-grade switch reliability with power failure, port interruption, relay output alarm, redundant dual DC power input, active circuit protection, overvoltage, undervoltage automatic trip protection, (depends on the model of reliability Different slightly different)
The functional difference mainly refers to: Industrial Ethernet switches are functionally similar to industrial networks, such as interworking and interconnection with various fieldbuses, redundancy of equipment, and real-time equipment; and the difference in performance is mainly reflected in In adapting to different external environmental parameters. The industrial environment has many special environments such as EMI (Electromagnetic Compatibility), temperature, humidity, and dust, in addition to many other harsh environments such as coal mines and ships. The impact of temperature on industrial network equipment is the most extensive.
This article mainly discusses the influence of temperature as an important parameter on industrial network switches. The parameters for functional aspects and other aspects of performance are not repeated here.
First, measure equipment reliability indicators <br> <br> Reliability refers to the conditions specified in the product and the prescribed time, the ability to complete specified functions. Any product, whether it is mechanical, electronic or mechatronic products, has a certain degree of reliability. The reliability of the product has a great relationship with the experiment, design and product maintenance.
There are many indicators for measuring reliability. The following are common:
1. Reliability R(t), that is, the probability of the product fulfilling the specified function within the specified time and within the specified time, also known as the mean time between failures MTBF (meantimebetweenfailure);
2. The mean time to repair, MTTR, is the time it takes for the product to recover from the discovery of a fault and return to a prescribed function.
3. The failure rate λ(t) refers to the probability of product failure after the product is used at the time t under the specified conditions of use. Changes in the reliability of products generally have a certain rule, and the characteristic curve is shaped like a bathtub, which is often called a bathtub curve. In the early stages of the experiment and design, due to errors in product design and manufacturing, incomplete software, and inadequate component selection, early failure rates are high; products are modified through design modification, process improvement, aging components, and overall testing. Into a stable accidental failure period; after using the general time, due to device wear, aging and maintenance of the whole machine, etc., the product has entered the consumption loss period. This is why the reliability profile is of the "tub curve" type. The most common measure of an electronic product, especially an industrial product, is MTBF, which is the average time between failures.
Second, the relationship between temperature and the MTBF <br> <br> since the density of electronic components used in modern electronic devices increasing, which will produce thermal coupling between the components by conduction, radiation and convection. Therefore, thermal stress has become one of the most important factors affecting the failure rate of electronic components. For some circuits, reliability is almost entirely dependent on the thermal environment. Therefore, in order to achieve the desired reliability, the temperature of the components must be reduced to the lowest level that can actually be achieved. Some data indicate that for every 10°C increase in ambient temperature, the life of components is reduced by about 1/2. This is the famous "10 °C rule."
MTBF test: At present, Bellcore's RPP (Reliability Prediction Procedure) is widely used abroad to measure the MTBF of a device, including the number of transistors, power attenuation, and environmental parameters. We analyze the test report of a 24-port network switch that is cooled by a fan. At an ambient temperature of 30°C, 40°C, and 50°C, the test results for a fanless switch and a fan switch are as follows:
30°C 40°C 50°C
No fan cooling 10 years 9.5 years 8 years There is fan cooling 8 years 7.5 years 7 years In addition, we also found two results in the TSC laboratory temperature test:
1. If no cooling measures are taken, a 24-port switch (without the optical port) operates normally for 4 hours. Its internal temperature is about 40°C higher than the surrounding ambient temperature; the fan-cooled same switch is used. The internal temperature is only about 15°C higher than the ambient temperature.
2. When the internal temperature reaches 85 °C, the temperature has actually begun to affect the life of many chip devices in the motherboard, that is, if you do not use good cooling measures, the external temperature is 45 ~ 50 °C, the switch MTBF will drop significantly.
It can be seen that the impact of temperature on industrial network products is very large. If a fan is used as a commercial switch to reduce the temperature, it can effectively reduce the internal temperature and extend the MTBF of the equipment, but the life of the fan itself is very limited (2.28 years) ( Data given by SANYOFANDATASHEET).
Industrial equipment is different from commercial equipment. It is often operated on a continuous basis, and the operating environment is often harsh. Sand, insects, and moisture all directly affect the operation of the fan. A good switch, the fan life is generally 20,000 hours, after the fan reaches the age limit, detection and replacement becomes very important. Because the active heat dissipation switch is mainly designed to use heat dissipation from the fan. Once the fan fails and is not replaced in time, the “10°C rule†will work: For every 10°C increase in ambient temperature, the life of the components will be reduced by 1/2. . The internal heat of the switch will quickly cause the performance of the switch to decrease until the switch crashes. Therefore, the design of the heat exchanger system of an industrial switch, that is, the thermal design is particularly important.
Third, the thermal design <br> <br> It is because of the influence of high temperature industrial network equipment is fatal, so in the design of these products, in addition to components of the device to select the wide temperature range of industrial grade components outside , It must pay more attention to the thermal design of the equipment.
The thermal design of electronic products mainly includes heat dissipation, installation of heat sinks, and cooling technologies. Here, the author mainly discusses the heat dissipation technologies in industrial network devices and the installation of heat sink technologies.
(I) Methods used in heat-dissipating applications The first method is the conductive heat-dissipation method. It is possible to use heat-conducting materials to make heat-conducting elements, or to reduce the thermal contact resistance and minimize the thermal path.
The second type is the convection cooling method. Convection cooling methods are natural convection cooling and forced convection cooling. Natural convection heat dissipation should pay attention to the following points:
l Extra space must be reserved when designing printed boards and components;
l When arranging components, pay attention to the reasonable distribution of the temperature field;
l Give full attention to the application of chimney ventilation principle;
l Increase the contact area with convection media.
Forced convection cooling methods can be used fan (such as a computer fan) or push-pull dual input mode (such as push-pull with a heat exchanger).
The third type is the use of heat radiation characteristics, which can be used to increase the surface roughness of the heating element, increase the ambient temperature difference around the radiator, or increase the surface area of ​​the radiator.
(II) Installation of Radiator Industrial Electronic Equipment In heat design, the most commonly used method is to install a heat sink whose purpose is to control the temperature of the semiconductor, especially the junction temperature Tj, which is lower than the maximum value of the semiconductor device. Temperature Tjmax, thereby improving the reliability of semiconductor devices. When the semiconductor device and the heat sink are installed and operated together, the heat resistance RTj, the junction temperature Tj, the case temperature Tc, the heat sink temperature Tf, the ambient temperature Ta, and the power Pc of the semiconductor device in the semiconductor device are included.
The thermal resistance of the heat sink RTf should be: RTf = (RTj-Ta) / Pc-RTj-RTc
Radiator thermal resistance RTf is the main basis for selecting a heat sink. Tj, RTj are the parameters that the semiconductor device offers, Pc is the parameter that the design demands, RTc can be found in the thermal design professional book. The following describes the choice of radiator.
1. The choice of natural cooling radiator first calculates the total thermal resistance RT and the thermal resistance RTf of the radiator, ie:
RT=(Tjmax-Ta)/Pc
RTf=RT-RTj-RT.
After calculating RT and RTf, the heat sink can be selected based on RTf and Pc. When selected, according to the selected heat dissipation RTf and Pc curve, the known Pc is found on the abscissa, and then the thermal resistance R'Tf of the heat sink corresponding to Pc is found.
According to the principle of R'Tf ≤ RTf, choose a reasonable radiator.
2. The choice of forced air-cooled radiator forced air-cooled radiator should be selected according to the heat resistance of the radiator RTf and wind speed to select the appropriate radiator.
3. The design of cooling fans The fans of ordinary commercial switches have been working at full speed (Full SPD). In addition to the waste of electrical energy and noise of the whole machine, it also increases the unnecessary heating of the power supply and excessive dust accumulation in the chassis. More importantly, when the fan is at full speed, its life is about 20,000 hours, which is 2.28 years (data given by SANYOFANDATASHEET). After 20,000 hours, the fan speed will gradually decrease, causing instability to the whole machine. However, because there is no monitoring unit, this hidden danger is difficult to find: For example, when the packet loss rate of the switch gradually increases, it is not easy to find that the aging speed of the fan is reduced and the dust accumulation is too thick to cause the temperature of key components in the chassis to rise.
Industrial switches should use high-speed (HighSPD) fans with intelligent monitoring circuits to monitor and control the operating status of network switches in real time, such as monitoring chassis fans, main switching chip temperature, chassis temperature, and optical transceiver temperature. Said "smart fan".
During the working process of the switch, the intelligent monitoring circuit will automatically adjust the fan speed according to the temperature of the component under test or the fan speed signal, and dissipate heat to the network switch. The speed of the fan is mainly related to the switch load and the ambient temperature. When the ambient temperature is constant, when the data load of the switch is reduced, the power consumption is reduced and the fan speed is automatically reduced. When the data load of the switch is increased, the power consumption is increased, and the fan speed is automatically increased. When the data load is fixed, the fan speed is automatically reduced when the switch is in a low temperature environment, and the fan speed is automatically increased when the switch is in a high temperature environment. Under high-temperature and high-load conditions, the fan can be in the HighSPD state, which can ensure the safe operation of the network compared to the full-SPD state.
4. The intelligent fan controller features intelligent fan control technology to extend fan life, reduce dust accumulation inside the machine, reduce fan noise, save power usage, and ensure efficient system operation. In addition, the controller can not only provide alarm for the fan stalling and temperature exceeding the warning line, but also provide corresponding risks for the early-stage hidden dangers such as aging or abnormal increase in duct resistance, lower than normal speed, or abnormal increase in temperature at the monitoring point. Chinese and English voice prompts make it easy for network managers to eliminate accidents in their infancy.
In summary, due to the particularity of the environment in which the Industrial Ethernet switch is located and the special characteristics of its use (it can not be downed), the countermeasures adopted when dealing with high and low temperatures, mainly high-temperature environments, are different from those of ordinary switches.
(1) For lower power conditions, generally when P≤10W, try not to use fan heat dissipation, but use natural heat dissipation if natural convection is adopted, or increase the area of ​​the housing, wrinkle the housing, or use a heat-conducting profile, such as aluminum. Wait.
(2) For the case of large power, when P≥15W, especially when there are multiple optical ports or even multiple single-mode optical ports, if the problem cannot be solved by natural heat dissipation, active heat dissipation should be used to solve the heat problem. . The active cooling method mainly refers to the installation of a fan. However, due to the special nature of the industrial network equipment that cannot be shut down and must be operated for a long time, the use of the fan should be considered as follows.
1 The fan is different from the fan of an ordinary electronic device. It should be intelligent. The intelligent fan has a qualitative difference in service life and function from ordinary fans.
2 The smart fan should be designed to be hot swappable, that is, if the system is not shut down, if the smart fan system alarms (working life expires, etc.), the fan can be replaced online. By adopting the above thermal design and heat dissipation measures, the MTBF of the network equipment can be greatly improved, and its life can be prolonged, thereby avoiding the law and allowing the components of the industrial network equipment to work in a stable and comfortable temperature environment for a long time. The 10°C rule does not work. This also ensures the stability and reliability of the communication system in the automation process.
The above information comes from the Internet!
In addition, the performance of the module expansion is more flexible than commercial switches: there are a variety of optical and electrical ports available for selection. It meets the needs of industrial sites in material selection, product strength, suitability and real-time, interoperability, reliability, anti-interference and intrinsic safety.
Industrial-grade design is generally designed to meet: industrial wide temperature design, 4 electromagnetic compatibility design, redundant AC and DC power input. In addition PCB board generally do "three defenses" processing.
Why should industrial sites use the right industrial Ethernet switches instead of cheap commercial switches? From the following aspects, we can determine the necessity of selecting industrial Ethernet switches in the industrial field.
1, due to the uncertainty <br> <br> a MAC layer protocol is Ethernet CSMA / CD, the protocol on the network such that there is a conflict, particularly when the network load is too large, more pronounced. For an industrial network, if there are a lot of conflicts, it is necessary to retransmit the data several times, so that the uncertainty of the inter-network communication increases greatly. This kind of uncertainty from one place to another in an industrial control network will inevitably bring about a reduction in the control performance of the system.
2, real-time <br> <br> in industrial control systems, real-time can be defined as a system testability of an event of reaction time. That is, after an incident occurs, the system must respond within a time frame that can be accurately predicted. However, the real-time requirements for data transmission in the industry are very strict, and often the data update is completed within several tens of ms. And because of the CSMA/CD mechanism that exists in Ethernet, when there is a conflict, you have to retransmit the data, and you can try at most 16 times. It is clear that this mechanism for resolving conflicts is at the expense of time. And once there is a drop, even if it is just a few seconds, it may cause the entire production to stop or even equipment, personal safety accidents.
3, the reliability of Ethernet <br> <br> Since early in the design, not the application from the industrial network. When it is applied to an industrial site, in the face of adverse conditions, severe line-to-line interference, etc., these will inevitably cause its reliability to decrease. Industrial networks must have good reliability, recoverability, and maintainability in a production environment. That is, to ensure that any component in a network system fails, it will not cause crashes and crashes in applications, operating systems, and even network systems.
Industrial Ethernet switches take into account the complexities of the industrial field when designing, so that they can adapt to the industrial environment and play the role of the switch.
The difference between IE switches and common switches is mainly reflected in their functions and performance.
The environment of the industrial site is worse than the ordinary environment. At least in vibration, humidity, and temperature, it must be inferior to the normal environment. The general switch is not designed to withstand the various situations that occur in the industrial environment. The ordinary switch cannot be long. Time works in such a hostile environment. It is often prone to failures and increases maintenance costs. It is generally not recommended to use commercial switches in an industrial environment. In order to enable the switch to be used in such harsh environments, the production can be adapted to Environmental switch, industrial-grade switch reliability with power failure, port interruption, relay output alarm, redundant dual DC power input, active circuit protection, overvoltage, undervoltage automatic trip protection, (depends on the model of reliability Different slightly different)
The functional difference mainly refers to: Industrial Ethernet switches are functionally similar to industrial networks, such as interworking and interconnection with various fieldbuses, redundancy of equipment, and real-time equipment; and the difference in performance is mainly reflected in In adapting to different external environmental parameters. The industrial environment has many special environments such as EMI (Electromagnetic Compatibility), temperature, humidity, and dust, in addition to many other harsh environments such as coal mines and ships. The impact of temperature on industrial network equipment is the most extensive.
This article mainly discusses the influence of temperature as an important parameter on industrial network switches. The parameters for functional aspects and other aspects of performance are not repeated here.
First, measure equipment reliability indicators <br> <br> Reliability refers to the conditions specified in the product and the prescribed time, the ability to complete specified functions. Any product, whether it is mechanical, electronic or mechatronic products, has a certain degree of reliability. The reliability of the product has a great relationship with the experiment, design and product maintenance.
There are many indicators for measuring reliability. The following are common:
1. Reliability R(t), that is, the probability of the product fulfilling the specified function within the specified time and within the specified time, also known as the mean time between failures MTBF (meantimebetweenfailure);
2. The mean time to repair, MTTR, is the time it takes for the product to recover from the discovery of a fault and return to a prescribed function.
3. The failure rate λ(t) refers to the probability of product failure after the product is used at the time t under the specified conditions of use. Changes in the reliability of products generally have a certain rule, and the characteristic curve is shaped like a bathtub, which is often called a bathtub curve. In the early stages of the experiment and design, due to errors in product design and manufacturing, incomplete software, and inadequate component selection, early failure rates are high; products are modified through design modification, process improvement, aging components, and overall testing. Into a stable accidental failure period; after using the general time, due to device wear, aging and maintenance of the whole machine, etc., the product has entered the consumption loss period. This is why the reliability profile is of the "tub curve" type. The most common measure of an electronic product, especially an industrial product, is MTBF, which is the average time between failures.
Second, the relationship between temperature and the MTBF <br> <br> since the density of electronic components used in modern electronic devices increasing, which will produce thermal coupling between the components by conduction, radiation and convection. Therefore, thermal stress has become one of the most important factors affecting the failure rate of electronic components. For some circuits, reliability is almost entirely dependent on the thermal environment. Therefore, in order to achieve the desired reliability, the temperature of the components must be reduced to the lowest level that can actually be achieved. Some data indicate that for every 10°C increase in ambient temperature, the life of components is reduced by about 1/2. This is the famous "10 °C rule."
MTBF test: At present, Bellcore's RPP (Reliability Prediction Procedure) is widely used abroad to measure the MTBF of a device, including the number of transistors, power attenuation, and environmental parameters. We analyze the test report of a 24-port network switch that is cooled by a fan. At an ambient temperature of 30°C, 40°C, and 50°C, the test results for a fanless switch and a fan switch are as follows:
30°C 40°C 50°C
No fan cooling 10 years 9.5 years 8 years There is fan cooling 8 years 7.5 years 7 years In addition, we also found two results in the TSC laboratory temperature test:
1. If no cooling measures are taken, a 24-port switch (without the optical port) operates normally for 4 hours. Its internal temperature is about 40°C higher than the surrounding ambient temperature; the fan-cooled same switch is used. The internal temperature is only about 15°C higher than the ambient temperature.
2. When the internal temperature reaches 85 °C, the temperature has actually begun to affect the life of many chip devices in the motherboard, that is, if you do not use good cooling measures, the external temperature is 45 ~ 50 °C, the switch MTBF will drop significantly.
It can be seen that the impact of temperature on industrial network products is very large. If a fan is used as a commercial switch to reduce the temperature, it can effectively reduce the internal temperature and extend the MTBF of the equipment, but the life of the fan itself is very limited (2.28 years) ( Data given by SANYOFANDATASHEET).
Industrial equipment is different from commercial equipment. It is often operated on a continuous basis, and the operating environment is often harsh. Sand, insects, and moisture all directly affect the operation of the fan. A good switch, the fan life is generally 20,000 hours, after the fan reaches the age limit, detection and replacement becomes very important. Because the active heat dissipation switch is mainly designed to use heat dissipation from the fan. Once the fan fails and is not replaced in time, the “10°C rule†will work: For every 10°C increase in ambient temperature, the life of the components will be reduced by 1/2. . The internal heat of the switch will quickly cause the performance of the switch to decrease until the switch crashes. Therefore, the design of the heat exchanger system of an industrial switch, that is, the thermal design is particularly important.
Third, the thermal design <br> <br> It is because of the influence of high temperature industrial network equipment is fatal, so in the design of these products, in addition to components of the device to select the wide temperature range of industrial grade components outside , It must pay more attention to the thermal design of the equipment.
The thermal design of electronic products mainly includes heat dissipation, installation of heat sinks, and cooling technologies. Here, the author mainly discusses the heat dissipation technologies in industrial network devices and the installation of heat sink technologies.
(I) Methods used in heat-dissipating applications The first method is the conductive heat-dissipation method. It is possible to use heat-conducting materials to make heat-conducting elements, or to reduce the thermal contact resistance and minimize the thermal path.
The second type is the convection cooling method. Convection cooling methods are natural convection cooling and forced convection cooling. Natural convection heat dissipation should pay attention to the following points:
l Extra space must be reserved when designing printed boards and components;
l When arranging components, pay attention to the reasonable distribution of the temperature field;
l Give full attention to the application of chimney ventilation principle;
l Increase the contact area with convection media.
Forced convection cooling methods can be used fan (such as a computer fan) or push-pull dual input mode (such as push-pull with a heat exchanger).
The third type is the use of heat radiation characteristics, which can be used to increase the surface roughness of the heating element, increase the ambient temperature difference around the radiator, or increase the surface area of ​​the radiator.
(II) Installation of Radiator Industrial Electronic Equipment In heat design, the most commonly used method is to install a heat sink whose purpose is to control the temperature of the semiconductor, especially the junction temperature Tj, which is lower than the maximum value of the semiconductor device. Temperature Tjmax, thereby improving the reliability of semiconductor devices. When the semiconductor device and the heat sink are installed and operated together, the heat resistance RTj, the junction temperature Tj, the case temperature Tc, the heat sink temperature Tf, the ambient temperature Ta, and the power Pc of the semiconductor device in the semiconductor device are included.
The thermal resistance of the heat sink RTf should be: RTf = (RTj-Ta) / Pc-RTj-RTc
Radiator thermal resistance RTf is the main basis for selecting a heat sink. Tj, RTj are the parameters that the semiconductor device offers, Pc is the parameter that the design demands, RTc can be found in the thermal design professional book. The following describes the choice of radiator.
1. The choice of natural cooling radiator first calculates the total thermal resistance RT and the thermal resistance RTf of the radiator, ie:
RT=(Tjmax-Ta)/Pc
RTf=RT-RTj-RT.
After calculating RT and RTf, the heat sink can be selected based on RTf and Pc. When selected, according to the selected heat dissipation RTf and Pc curve, the known Pc is found on the abscissa, and then the thermal resistance R'Tf of the heat sink corresponding to Pc is found.
According to the principle of R'Tf ≤ RTf, choose a reasonable radiator.
2. The choice of forced air-cooled radiator forced air-cooled radiator should be selected according to the heat resistance of the radiator RTf and wind speed to select the appropriate radiator.
3. The design of cooling fans The fans of ordinary commercial switches have been working at full speed (Full SPD). In addition to the waste of electrical energy and noise of the whole machine, it also increases the unnecessary heating of the power supply and excessive dust accumulation in the chassis. More importantly, when the fan is at full speed, its life is about 20,000 hours, which is 2.28 years (data given by SANYOFANDATASHEET). After 20,000 hours, the fan speed will gradually decrease, causing instability to the whole machine. However, because there is no monitoring unit, this hidden danger is difficult to find: For example, when the packet loss rate of the switch gradually increases, it is not easy to find that the aging speed of the fan is reduced and the dust accumulation is too thick to cause the temperature of key components in the chassis to rise.
Industrial switches should use high-speed (HighSPD) fans with intelligent monitoring circuits to monitor and control the operating status of network switches in real time, such as monitoring chassis fans, main switching chip temperature, chassis temperature, and optical transceiver temperature. Said "smart fan".
During the working process of the switch, the intelligent monitoring circuit will automatically adjust the fan speed according to the temperature of the component under test or the fan speed signal, and dissipate heat to the network switch. The speed of the fan is mainly related to the switch load and the ambient temperature. When the ambient temperature is constant, when the data load of the switch is reduced, the power consumption is reduced and the fan speed is automatically reduced. When the data load of the switch is increased, the power consumption is increased, and the fan speed is automatically increased. When the data load is fixed, the fan speed is automatically reduced when the switch is in a low temperature environment, and the fan speed is automatically increased when the switch is in a high temperature environment. Under high-temperature and high-load conditions, the fan can be in the HighSPD state, which can ensure the safe operation of the network compared to the full-SPD state.
4. The intelligent fan controller features intelligent fan control technology to extend fan life, reduce dust accumulation inside the machine, reduce fan noise, save power usage, and ensure efficient system operation. In addition, the controller can not only provide alarm for the fan stalling and temperature exceeding the warning line, but also provide corresponding risks for the early-stage hidden dangers such as aging or abnormal increase in duct resistance, lower than normal speed, or abnormal increase in temperature at the monitoring point. Chinese and English voice prompts make it easy for network managers to eliminate accidents in their infancy.
In summary, due to the particularity of the environment in which the Industrial Ethernet switch is located and the special characteristics of its use (it can not be downed), the countermeasures adopted when dealing with high and low temperatures, mainly high-temperature environments, are different from those of ordinary switches.
(1) For lower power conditions, generally when P≤10W, try not to use fan heat dissipation, but use natural heat dissipation if natural convection is adopted, or increase the area of ​​the housing, wrinkle the housing, or use a heat-conducting profile, such as aluminum. Wait.
(2) For the case of large power, when P≥15W, especially when there are multiple optical ports or even multiple single-mode optical ports, if the problem cannot be solved by natural heat dissipation, active heat dissipation should be used to solve the heat problem. . The active cooling method mainly refers to the installation of a fan. However, due to the special nature of the industrial network equipment that cannot be shut down and must be operated for a long time, the use of the fan should be considered as follows.
1 The fan is different from the fan of an ordinary electronic device. It should be intelligent. The intelligent fan has a qualitative difference in service life and function from ordinary fans.
2 The smart fan should be designed to be hot swappable, that is, if the system is not shut down, if the smart fan system alarms (working life expires, etc.), the fan can be replaced online. By adopting the above thermal design and heat dissipation measures, the MTBF of the network equipment can be greatly improved, and its life can be prolonged, thereby avoiding the law and allowing the components of the industrial network equipment to work in a stable and comfortable temperature environment for a long time. The 10°C rule does not work. This also ensures the stability and reliability of the communication system in the automation process.
The above information comes from the Internet!
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