Different wireless technologies for special industrial requirements.
In industry there is a vast range of applications for wireless technologies, from the transmission of a simple sensor value through to a powerful network with hundreds of devices. This means that the requirements for wireless technology differ significantly.
This broad range of requirements cannot be covered entirely by a single wireless technology. Phoenix Contact offers products and solutions for four different license-free and free of charge wireless technologies which can cover virtually all industrial areas of application.
|Bluetooth||Trusted Wireless 2.0||WirelessHART||Wireless LAN|
|Wireless standard||IEEE 802.15.1||Phoenix Contact in-house development||IEEE 802.15.4||IEEE 802.11|
|Frequency band||2.4 GHz||868 MHz, 900 MHz, 2.4 GHz||2.4 GHz||2.4 GHz, 5 GHz|
|Working range with line of sight||< 250 m||32 km (900 MHz)|
20 km (868 MHz)
5 km (2.4 GHz)
|< 250 m||< 1 km|
|Working range in an industrial hall||< 100 m||< 250 m||< 100 m||< 100 m|
|Topology||Point-to-point, star||Point-to-point, star, mesh||Full mesh||Point-to-point, star, mesh|
|Data rate||Up to 3 Mbps||Up to 500 kbps||Up to 250 kbps||Up to 300 Mbps|
|Latency||A few ms||> 200 ms, depending on the frequency band, OTA data rate, and network structure||> 3 s||A few ms|
|Shortest update time||16 ms with PROFINET||4 ms with PROFINET|
|Coexistence with WLAN||Very good||Very good||Good||Very good with good planning|
|Robustness with regard to failures||Very good||Very good||Very good||Good|
|Typical application||PROFINET, PROFIBUS (serial data)||I/O data, serial data||HART data||Ethernet, PROFINET, EtherNet/IP™|
|Functional Safety||Suitable for PROFIsafe and SafetyBridge applications||No||No||Suitable for PROFIsafe and SafetyBridge applications|
Bluetooth and Wireless LAN solutions and products from Phoenix Contact are standard-compliant. The industrial wireless technologies do, however, differ significantly from standard products for consumer and office applications.
Unique to industrial communication is the fact that relatively small data packets need to be transmitted cyclically with a short update time. The reliability of the communication is decisive here. Even the smallest dropouts or interruptions to communication can bring production to a standstill and therefore incur consequential costs. Special, robust industrial hardware is key to permanently reliable 24/7 wireless communication.
In contrast to a well protected cable connection, the transmission medium in wireless industrial communication is supplied without protection against interference. In order to guarantee a sufficient transmission quality, various mechanisms have been implemented in the wireless technology itself as well as in the industrial wireless modules.
These include error correction and spread spectrum systems, redundant data transmission or MIMO (Multiple Input, Multiple Output) antenna technology. The high transmission frequency itself provides protection against various, sometimes very strong electromagnetic interferences in industrial environments: typical industrial interferences, such as those from frequency inverters, usually occur in the lower frequency range (kHz, MHz). Wireless communication is not affected by this as it takes place above 2.4 GHz.
Electromagnetic interference that occurs in the high frequency bands is often caused by other wireless applications on the same frequency. A basic prerequisite for uninterrupted wireless operation is therefore frequency planning in which every application is assigned its own frequency range. Generally speaking, interference only occurs if its cause occurs at the same time, in the same place, and in the same frequency range.
Since it is very hard to limit the physical range of the wireless field, security measures are a must in wireless communication. These prevent data from being manipulated or read. Most wireless systems already include technical security measures that satisfy the current standard of IT safety technology and enable secure wireless networks to be constructed. The latest and most secure encryption procedures must always be used for the wireless systems.
Technical measures alone are not sufficient for network security, however. The operator must also implement organizational measures. Under Further information you will find links to the corresponding pages of the VDI and the Federal Office for Information Security (BSI). These describe in detail how to protect (wireless) networks. On request you can also receive comprehensive advice from our Industrial Wireless experts.
Since wireless data transmission involves high-frequency electromagnetic fields, the question remains as to whether this poses a health risk. The specific absorption rate (SAR), which is also used to measure energy absorption from cell phones, is used as the basis for assessing this. The SAR describes how much radiated power is absorbed by the human body in a particular situation.
According to current knowledge, there are no harmful effects on the human body provided the recommended maximum values are observed. The SAR values for radio waves from Bluetooth or WLAN devices generally remain far below the recommended radiated power, particularly when operated at a distance from the body. Links to further information on this subject can be found under Links.
Wireless systems are often used to communicate with mobile or moving systems. Movement often involves a risk to persons and property. In such cases functionally safe communication along the wireless path is essential. The simplest solution is to use Ethernet-based safety protocols such as PROFIsafe or SafetyBridge technology, which can be transmitted safely via Bluetooth or WLAN wireless paths. The reason: the safety measures for safe end-to-end communication by PROFIsafe and SafetyBridge are implemented independently of the transmission channel, often referred to as the black channel.
Standard network components and Wireless LAN or Bluetooth modules can be used in the so-called black channel as these do not need to be validated according to the safety standards of the IEC 61508 series. The safety protocol detects errors or timeouts in the communication and automatically switches the application to the safe state. To ensure that the productivity of the machine or system is not adversely affected by frequent interruptions to communication, a robust and reliable solution for wireless transmission is essential.