Preface Wireless technologies have become increasingly popular in industrial automation as growing numbers of system integrators, governmental agencies, and industrial solution providers continue to turn to these solutions for their applications. Advantages of using wireless technologies include boosting data transmission speed, real-time data transmissions, remote equipment monitoring and alerts, flexible installation of remote equipment, and wide coverage areas.
2.3 Antenna Theory and Selection---------------- 21 Functions of Antennas Types of Antenna Key Antenna Specifications Choosing the Right Antenna for Your Project 2.4 Long Distance Wireless----------------------- 23 Application Topology Components of the Expanded 802.11 Wireless System Moxa’s Antennas Selection Guide------------ 30 IEEE 802.11b/g 2.4 GHz Wireless Antennas IEEE 802.11a/b/g 2.4/5 GHz Dual-band Antennas IEEE 802.
Differentiating Between Wireless Technologies Chapter 1 Differentiating Between Wireless Technologies 1.1 WWAN vs. WLAN vs. WPAN Modem wireless technologies are developed for the growing demand in mobile data exchange. Since demands vary depending on the application, different technologies are applied to meet specific needs. Normally, wireless technologies are divided into three categories: WWAN, WLAN and WPAN.
2009 Industrial Wireless Guidebook WPAN (Wireless Personal Area Network) A WPAN is a short-range peer-to-peer or ad hoc network built around a person’s working area. Normally the distance is no more than 10 meters. Because of their limited transmission range, WPANs are used mainly as cable replacement solutions for data synchronization and data transmission for personal electronic devices such as PDAs or smart phones. Bluetooth is the most prevalent WPAN technology in use today.
Differentiating Between Wireless Technologies CDMA2000 1xEV (Evolution) CDMA2000 1xEV is CDMA2000 1x equipped with HDR. 1xEV, in general, has two sessions: • CDMA2000 1xEV 1st session—CDMA2000 1xEV-DO, in light of the fast data transmitted under a wireless channel, supports downlink data speeds up to 3.1 Mbps with uplink up to 1.8 Mbps. • CDMA2000 1xEV 2nd session—CDMA2000 1xEV-DV (Evolution-Data and Voice) supports downlink data speeds up to 3.1 Mbps with uplink up to 1.8 Mbps.
2009 Industrial Wireless Guidebook Despite WiMax’s current lead in commercializing its technologies, there are signs indicating that LTE is catching up. In the past, major players like Nokia, Siemens, Motorola, Alcatel, Lucent, and Nortel showed their support for WiMax. But starting from 2008, these players were also showing signs of interests in LTE. Nortel had announced not to take part in Mobile WiMax.
Differentiating Between Wireless Technologies 1.3 Evolution of IEEE 802.11 With the advent and development of local area networks (LAN), IEEE 802.3 has been widely adopted in many different kinds of communication applications. The continued prevalence of wired communication has also contributed to the growing demand for wireless communication. In 1997, IEEE released the IEEE 802.
2009 Industrial Wireless Guidebook IEEE 802.11n In January 2004, IEEE made an announcement to form a new task force to develop new standards for the IEEE 802.11 standard. The goal of this task force was to allow wireless communication speed to reach a theoretic number of 300 Mbps. Since the theoretic speed of this new standard, now called IEEE 802.11n, needs to reach 300 Mbps, the Physical Layer also needs to support a higher transmission speed that is at least 50 times faster than IEEE 802.
Differentiating Between Wireless Technologies 1.4 WLAN vs. Proprietary 2.4GHz Common usage of the WLAN limits its distance to under 100 meters. Now with Moxa’s advanced technologies, it is also possible to extend the distance up to 10 kilometers for multi-point connections or 20 kilometers for point-topoint connections. The IEEE 802.11 standard is designed for high-speed data transmission. However, it is also vulnerable to outside interferences.
2009 Industrial Wireless Guidebook Chapter 2 Understanding Industrial WLAN – IEEE 802.11 2.1 IEEE 802.11 Basics Wireless Communication In a wireless environment, the communication medium is air. Radio waves carrying data propagate from point to point through free space. Due to the characteristics of this unguided medium, wireless communication calls for a very different set of knowledge and skills than traditional wired communication systems.
Understanding Industrial WLAN – IEEE 802.11 Diffraction (Shadow Fading) Signal strength is reduced after experiencing diffraction. Obstacles causing diffraction usually possess sharp edges such as the edges of buildings. When EM waves encounter an obstacle with sharp edges that cannot be penetrated, the EM waves wrap around the obstacle to reach the receiver.
2009 Industrial Wireless Guidebook DSSS (Direct Sequence Spread Spectrum) DSSS divides a stream of information to be transmitted into small pieces, each of which is allocated to a frequency channel across the spectrum. DSSS generates a redundant bit pattern for each bit to be transmitted. This bit pattern is called a chip (or chipping code).
Understanding Industrial WLAN – IEEE 802.11 Lastly, let’s use the 802.11g standard as an example for how the transmission type and modulation scheme corresponds to each data rate: 802.11g Data Rate (Mbps) Transmission Type Modulation Scheme 54 OFDM 64 QAM 48 OFDM 64 QAM 36 OFDM 16 QAM 24 OFDM 16 QAM 18 OFDM QPSK1 12 OFDM *a QPSK 11 DSSS CCK2 *a QPSK: Quadrature Phase Shift Keying 9 OFDM BPSK3 6 OFDM *b CCK: Complementary Code Keying 5.
2009 Industrial Wireless Guidebook 2.4 GHz ISM Band As 802.11b/g is the most commonly used WLAN standard today, the 2.4 GHz ISM band is supported by almost every country worldwide. Not every country supports the same channels in the 2.4 GHz ISM band, so you need to make sure the wireless AP matches the standard used by your country. The following chart shows channels supported in the 2.4 GHz ISM band for different countries/continents. Channel Number Center Frequency USA EU, M. East, Asia Japan 1 2.
Understanding Industrial WLAN – IEEE 802.11 UNII Band The 5 GHz UNII band consists of 3 parts, each 100 MHz wide. The 802.11a standard uses this band. Each part of the UNII band includes 4 non-overlapping channels with 5 MHz of guard band between them. The FCC states that the lower band (UNII-1) can only be used indoors, the middle band (UNII-2) can be used indoors or outdoors, and the higher band (UNII-3) should only be used outdoors.
2009 Industrial Wireless Guidebook The following table shows some common conversion values between dBm and mW: dBm Watt dBm Watt +40dBm 10W +12dBm 16mW +30dBm 1W +9dBm 8mW +20dBm 100mW +6dBm 4mW +10dBm 10mW +3dBm 2mW 0dBm 1mW 0dBm 1mW -10dBm 100uW -3dBm 500uW -20dBm 10uW -6dBm 250uW -30dBm 1uW -9dBm 125uW -40dBm 100nW -12dBm 62.5uW In dealing with antenna gain specifications, the gain factor is often represented by “dBi”.
Understanding Industrial WLAN – IEEE 802.11 The receiver’s sensitivity is the minimum power level the receiver can accept to process the received data. The specified sensitivity is not the power detected by the receiving antenna but the power present as the receiver module. An important point to note from the above equation is that as frequency increases, the effective distance decreases. Therefore, the 802.11a (5 GHz) standard will yield a shorter communication distance than 802.11b/g (2.4 GHz).
2009 Industrial Wireless Guidebook 2.2 Wireless Security If you’re new to wireless, the first thing you should realize is that the signals you send and receive from a nearby access point are easily intercepted by anyone in the vicinity who has a wireless card and a computer. The purpose of WLAN security techniques is to render the connection unusable and the data unreadable by anyone but you and the person (or machine) you’re communicating with.
Understanding Industrial WLAN – IEEE 802.11 Encryption The science of encryption or, in more down-to-earth terms, the making and breaking of codes, is one of the most crucial aspects of WLAN technology. This is because the radio waves used to transmit data packets between your computer and the wireless access point can pass through walls, floors, and other barriers.
2009 Industrial Wireless Guidebook Using a Firewall as an Additional Safeguard One of the most basic aspects of maintaining the security of your network involves using a firewall to filter out unwanted traffic. To protect a private LAN from unwanted traffic originating outside the LAN, firewall software often runs on a gateway that connects the LAN to the Internet.
Understanding Industrial WLAN – IEEE 802.11 2.3 Antenna Theory and Selection Choosing the right antenna after a site survey is a small but important factor when planning a wireless project. The purpose of this section is to explain what an antenna is and how to choose the right antenna to help build a reliable wireless network. Functions of Antennas An antenna is a transducer that is designed to transmit or receive electromagnetic waves.
2009 Industrial Wireless Guidebook Frequency Different wireless applications use different frequencies to achieve their purposes. To make sure wireless devices work as expected, users need to choose the right antenna with the right frequency. For example using a 5GHz IEEE 802.11a application with a 2.4GHz antenna can weaken or even completely wipe out the signal.
Understanding Industrial WLAN – IEEE 802.11 2.4 Long Distance Wireless Wireless transmissions today are based upon the IEEE 802.11 protocol stacks. By modifying these stacks, wireless solution providers can optimize them for long-range, point-to-point applications. It has also been used in the developing world to link communities separated by difficult geography with little or no connectivity options.
2009 Industrial Wireless Guidebook Wireless Bridge System (Dual RF) Moxa’s proprietary Wireless Bridge System (Dual RF) allows several buildings on a corporate campus to be connected to the central office. The central AP is configured as the “master” device and the remote client stations as “slave” devices. The wireless link will not reduce the bandwidth (to due to the use of Dual RF and isolation of the overlap frequency channel) but will extend the wireless range.
Understanding Industrial WLAN – IEEE 802.11 Components of the Expanded 802.11 Wireless System Expanded 802.11 wireless systems consist of the following components, some of which are optional. Access Points Moxa supplies 802.11a/b/g/n (802.11n will be implemented in the future, the technology works by using multiple antennas to target one or more sources to increase transmission power and throughput) wireless AP/Bridge/Client devices to extend the wireless range. IEEE 802.
2009 Industrial Wireless Guidebook External Antennas Moxa’s 802.11a/b/g/n wireless AP/bridge/client devices are supplied with a low gain antenna. However, for many of the long range applications, additional external antennas are necessary to extend the wireless range. The following sections contain a brief description of the two types of antennas: • Omni-directional antennas transmit horizontally with equal power in all directions. They have very limited vertical spread, which determines the antenna gain.
Understanding Industrial WLAN – IEEE 802.11 Setting Up Point-to-Point Connections This sector introduces the basic principles involved in designing point-to-point links and provides tips on aligning the antennas.
2009 Industrial Wireless Guidebook To ensure that the Fresnel Zone remains unobstructed, the height of the antennas must exceed that of the highest obstruction by this radius. The figure below shows the full height of the antenna mast. Antenna Gains Antenna Alignment for P2P Operations When there is not enough obstacle-free Fresnel Zone available, you may need to relocate the wireless devices or elevate the antennas to clear more Fresnel Zone space (see figure below).
Understanding Industrial WLAN – IEEE 802.11 The precise alignment of the antennas is of considerable importance in establishing long range wireless connections. The more central the receiving antenna is located in the “ideal line” of the transmitting antenna, the better the actual performance and the effective bandwidth are. If the receiving antenna is outside of this ideal area, however, significant losses in performance will result.
2009 Industrial Wireless Guidebook Moxa’s Antennas Selection Guide IEEE 802.11b/g 2.4 GHz Wireless Antennas ANT-WSB-ANF-09 ANT-WSB-PNF-12 ANT-WSB-PNF-18 E-Plane E-Plane E-Plane E-Plane H-Plane H-Plane H-Plane H-Plane Frequency Range 2.4 to 2.5 GHz 2.4 to 2.5 GHz 2.4 to 2.5 GHz 2.4 to 2.
Understanding Industrial WLAN – IEEE 802.11 IEEE 802.11a/b/g 2.4/5 GHz Dual-band Antennas Product Name ANT-WDB-ANF-0609 E-Plane (2.4 GHz) E-Plane (5 GHz) ANT-WDB-PNF-1518 E-Plane (2.4 GHz) E-Plane (5 GHz) H-Plane (2.4 GHz) H-Plane (5 GHz) Antenna Patterns H-Plane (2.4 GHz) 31 H-Plane (5 GHz) Frequency Range 2.4 to 2.5 / 5.1 to 5.9 GHz 2.4 to 2.5 / 5.1 to 5.
2009 Industrial Wireless Guidebook IEEE 802.11a 5 GHz Wireless Antennas Product Name ANT-WSB5-ANF-12 E-Plane ANT-WSB5-PNF-18 E-Plane 2 H-Plane H-Plane Frequency Range 5.1 to 5.9 GHz 5.1 to 5.9 GHz Antenna Type Omni-directional Directional, Panel Typical Antenna Gain 12 dBi 18 dBi Impedance 50±5 ohms 50±5 ohms Polarization Linear Linear Linear HPBW/Horizontal 360° 10° HPBW/Vertical 6° 10° V.S.W.R. 1 : 1.3 Max. 1 : 1.5 Max. Power Handling 10 W Max. 10 W Max.
Understanding Industrial WLAN – IEEE 802.11 Cellular Antennas GSM/GPRS Cellular Antennas Product Name ANT-CQBASM-01 ANT-CQBAHSM-00-3m ANT-CQBAHSM-03-3m ANT-CQBAHSM-05-3m Frequency Range 850/900/ 1800/1900 MHz 850/900/ 1800/1900 MHz 850/900/ 1800/1900 MHz 850/900/ 1800/1900 MHz 850/900/1800/ 1900/2100 MHz 850/900/1800/ 1900/2100 MHz Cable Type --- RG174/U RG174/U RG174/U --- RG174/U Typical Antenna Gain max. 1 dBi 0 dBi 3 dBi 5 dBi 1.
2009 Industrial Wireless Guidebook Moxa Performance Test Report ANT-WDB-O-2(Omni dipole dual band 2dBi antenna) Distance(Km) 2.4G-AP Station (Mbps) 2.4G-Station 5G-AP 0.1 AP (Mbps) Station (Mbps) 5G-Station AP (Mbps) 0.2 0.5 1 18.38 16.62 7.869 4.471 20.13 17.471 6.82 4.008 20.371 11.725 12.959 N/A 19.068 13.637 13.123 N/A N/A: Not Available ANT-WSB-ANM-05(Omni dipole 2.4G 5dBi antenna) Distance(Km) 2.4G-AP Station (Mbps) 2.4G-Station AP (Mbps) 0.1 0.2 0.5 1 24.257 17.
Understanding Industrial WLAN – IEEE 802.11 2.5 Mobile Optimization In mobile applications that involve multiple access points (APs), the speed and roaming (handover) mechanism can be crucial to a project’s success. In the world of wireless, roaming refers to when a client moves between two or more access points. As a result, seamless connection is required for the client to roam from one AP to another.
2009 Industrial Wireless Guidebook Roaming Speed Acceleration To increase the roaming speed, a common method is to use the Threshold-based Handover Algorithm. 2 In short, the Threshold-based Handover Algorithm means the client will constantly scan for the best AP signal quality and roam only when the threshold is reached. This can prevent the ping-pong effect, unnecessary handovers that might take place when the client moves back and forth between two APs.
Understanding Industrial WLAN – IEEE 802.11 2.6 Advanced WLAN Technologies Dual RF Redundancy According a recent VDC report, more than 40% of wireless users are concerned about interference. In industrial and critical applications, this issue is even more important. Normally, interference occurs in a dedicated frequency. So, if we can use 2 or more different frequencies to communicate at the same time, then data transmission will not be stopped, even if there is interference in one of the frequencies.
2009 Industrial Wireless Guidebook Introduction to Moxa’s Dual RF Redundancy Moxa’s advanced AP/Client AWK-5000/6000 series product line provides this kind of redundancy. The configuration is very easy. All you need to do is select redundant AP on the AP side and redundant Client on the client side. Then, set a different SSID for each RF. As shown in the following figure depicting the Web console UI for Moxa’s AWK-5222, set SSID1 for WLAN1 and SSID2 for WLAN2.
Understanding Industrial WLAN – IEEE 802.11 Figure: Wireless Bridge Mode Wireless Bridge mode can also connect wireless clients to another SSID, as shown below, so it can be used in environments where APs cannot be wired. Figure: Bridge Mode for Extra APs Mesh Technologies Mesh technologies are generally considered to be wireless communication systems that are interconnected to each other.
2009 Industrial Wireless Guidebook Wireless VLAN A Virtual LAN (VLAN), as defined in IEEE, is a group of hosts grouped together as if they were attached to the Broadcast domains in a Layer 2 network. Traditional networks use routers to define broadcast domain, but it is now possible to set the broadcast domain boundaries with Layer 2 switches. That is to say, a VLAN can add two or more hosts that were in different subnets to be grouped into the same LAN segment disregard of their geographical locations.
Understanding Industrial WLAN – IEEE 802.11 QoS for Video/Audio and Control The dramatic growth of WLAN has also led to demands for video and audio transmission over WLAN. Quality of Service (QoS) is therefore becoming an important topic for wireless communications. QoS is a network term for controlling and measuring data transmission rates, throughputs and error rates. QoS is not of a big concern for simple data transmission.
2009 Industrial Wireless Guidebook 2.7 Industrial Certification EN50155 Certification EN50155 are the standards that define requirements for railway cars, or rolling stock. It clearly outlines the requirements for power input voltage fluctuation, transient, ambient temperature ranges, shock and vibration and as well as fog and salt spray. Electronics that are used aboard railway rolling stock are required to meet the standards of EN50155.
Understanding Industrial WLAN – IEEE 802.11 ATEX/Class I Division 2 ATEX is the term used when referring to the European Unions (EU) Directive 94/9/EC. ATEX governs the regulations on the equipment used in potentially explosive atmospheres. All equipment meeting the requirements are free to circulate within EU boarders. The directive applies to all equipment or protective systems used in areas subject to explosion risks, gas vapors, mist, or dust.
2009 Industrial Wireless Guidebook Chapter 3 Cellular Networks 3.1 Cellular Basics What is Cellular? Cellular is a radio based communications system that enables customers to call and be reached over a wide area, supporting both hand-over and roaming. Cellular networks are connected to the PSTN to give transparent incoming and outgoing access to fixed network subscribers.
Cellular Networks Short Message Services (SMS) SMS messages, as specified by the ETSI organization (documents GSM 03.40 and GSM 03.38) and can be up to 160 characters long, where each character is 7 bits according to the 7-bit default alphabet. Eightbit messages (max. 140 characters) are usually not viewable on phones as text messages. Instead, they are used for data in 16-bit messages (max. 70 characters) and used for Unicode (UCS2) text messages viewable on most phones.
2009 Industrial Wireless Guidebook Packet Switching Data Solution: GPRS General Packet Radio Service (GPRS) provides Packet Switching service to GSM systems. A GSM system is traditionally a Circuit Switching network that provides optimized voice transmission service. For instance, a call between Party A and Party B will exclude other parties. Even if Party A and Party B temporarily fall into silence during their conversation, the call (network resource) won’t be released until either end hangs up.
Cellular Networks APN in Packet Switch Each external network is given a unique Access Point Name (APN) that is used by the mobile user to establish the connection to the required destination network. PDP context activation procedures are as follows: 1. Mobile phone sends out PDP context activation request and other relative parameters (e.g.,APN, QoS) 2. SGSN begins verification based on previously stored GPRS Attach information 3. DNS mechanism in SGSN analyzes the APN and returns a GGSN address 4.
2009 Industrial Wireless Guidebook 3.2 Private IP Solution There are two limiting factors you are almost assured to encounter when setting up a wired LAN with private IP addresses in an office: (1) short transmit latency and (2) limited IP addresses to connect to the Internet for the cellular WAN interface. As a result, delay times for the WAN interface are very different from the local area network’s delay times. WAN port IP addresses are also very different from those in office LANs. Private IP vs.
Cellular Networks As a result of WAN latency from cellular networks, you cannot count the number of nodes in your link as the timing is different for each link. Therefore, delay time in cellular networking is immeasurable and not suitable for real-time systems. Solution for Private IP A common problem in M2M network planning is that cellular operators and service providers usually only provide private and dynamic IP addresses. The reasons for doing so are threefold: 1.
2009 Industrial Wireless Guidebook 3.3 Security One of the major concerns faced by system integrators when adopting an Ethernet solution is the security and confidentiality of data transmissions over the network. Wireless networks are especially vulnerable because they need to transmit data through open air and are vulnerable to sniffing. To protect the security of wireless connections, one of the most commonly seen solutions is the VPN.
Cellular Networks 3.4 How to Connect Serial Devices to Cellular Networks Traditional Modems Serial port connections are very popular in traditional industrial applications but their transmission distance is limited. The Hayes command modem (AT command) offers a good solution for enlarging the transmission distance. It connects two serial devices through PSTN via an AT modem.
2009 Industrial Wireless Guidebook • Depending on whether the OnCell G3100 device is acting in a Client role or Server role, the user can select Real COM mode or Reverse Real COM mode. Normally, the role of the OnCell G3100 device depends on the IP address obtained from your cellular service provider. If your OnCell G3100 device’s SIM card is able to obtain a public IP address, then the OnCell device can act as a Server and you can select Real COM mode to connect the host PC (Client role).
Cellular Networks Socket Mode, Standard TCP IP Connection (TCP Server/Client) If your application involves a socket-based TCP server or TCP client, you can set your OnCell G3100 device to Socket Mode Socket operation mode by simply using the OnCell web console. You do not need to install any additional utilities onto the host PC but the socket software on the host PC will need to set up a socket connection with the OnCell G3100.
2009 Industrial Wireless Guidebook Short Message Connection (SMS Tunnel) Short Message Service (SMS) is a very popular service offered by cellular providers. You can send and receive serial data via SMS by setting up the OnCell G3100 device’s SMS Tunnel Mode. The OnCell G3100’s SMS Tunnel Mode uses a serial port to serial port communication tunnel to send SMS messages. There are 3 key inputs involved in transmitting SMS serial data. 1.
Cellular Networks 2.The originating OnCell device dials the phone number of the ISP (Internet Service Provider) just like an analog modem. Normally, ISPs offer free accounts and passwords for you to access the Internet. PPP to Internet via ISP IP Gateways and GPRS GPRS is designed for packet data communication and provides GSM users with access to the Internet from a cellular network.
2009 Industrial Wireless Guidebook 3.5 How to Connect Ethernet Devices to Cellular Networks Traditionally, Ethernet-based devices can only establish TCP/IP connections through wired LAN lines. At best, you may be able to deploy a WLAN environment to communicate with Ethernet devices in the field. A WLAN system can eliminate wires and cabling problems when installing and operating the devices. It also provides greater mobility, especially when the Ethernet devices are moving.
Cellular Networks How to configure the OnCell device as a virtual server In the OnCell device’s web console, you will find a virtual server settings page where you can set up multiple Ethernet devices connected to the OnCell device: As you can see, virtual server setting is basically setting the forwarding ports. For example, you select an available public port that the OnCell’s WAN IP will be listening on.
2009 Industrial Wireless Guidebook From LAN to WAN 3 We now switch the role of the Ethernet device from TCP Server to TCP Client: When the OnCell is acting as a client, its WAN IP address will not be limited to public WAN IP addresses. The WAN IP address of the OnCell IP modem can be public or private, static or dynamic without any extra settings.
Cellular Networks 3.6 How to Connect I/O Devices to Cellular Networks SCADA Meets Ethernet SCADA (Supervisory Control and Data Acquisition) is a computer-based industrial control system that plays an important role in the field of automation today.
2009 Industrial Wireless Guidebook The SCADA system reads the measured flow and level, and sends the setpoints to the PLCs PLC2 compares the measured level to the setpoint, controls the flow through the valve to match level to setpoint ‘‘Mix-and-Match” SCADA SCADA/HMI systems evolved in three stages, including Monolithic, Distributed, and Network SCADA systems. Monolithic SCADA involves an independent system for single station and uses a vendor’s proprietary communication protocols.
Cellular Networks Although it allows different equipment from different vendors to communicate with each other, it does not utilize the bi-directional and “push” technology advantages of Ethernet networks. For example, if an intelligent device wanted to send alarms and execute front-end logic, it could take advantage of Ethernet network communication technology used in IT. The vast majority of markets have accepted Ethernet networks for their HMI/SCADA systems.
2009 Industrial Wireless Guidebook General OPC servers typically use the “poll/response,” or so-called “pull” architecture, to connect to Ethernet I/O devices, which involves an HMI/SCADA system continuously sending out commands to collect relevant data.
Cellular Networks Automatic Tag Generation Active OPC Server Lite and ioLogik series products support “Auto Tag Generation,” which eliminates the headache of specifying target IP addresses, I/O channels, and data formats one by one, or editing and importing configuration text files, since Active OPC Server Lite creates the tags for the target ioLogik automatically. Simply select the channels that you need to update, and the tags are generated and configured automatically.
2009 Industrial Wireless Guidebook General OPC Architecture and Components The architecture of OPC leverages the advantages of the COM interface, which provides a convenient mechanism to extend the functionality of OPC. OPC specifications always contain two sets of interfaces; Custom Interfaces and Automation interfaces. 3 Cellular Networks The OPC Specification specifies the COM interfaces but not the implementation.
Cellular Networks OPC and DCOM: 5 Things You Need to Know OPC technology relies on Microsoft’s COM and DCOM to exchange data between automation hardware and software; however it can be frustrating for new users to configure DCOM properly. If you have ever been unable to establish an OPC connection or transfer OPC data successfully, the underlying issue is likely DCOM-related. In the following, we will discuss the steps necessary to get DCOM working properly and securely.
2009 Industrial Wireless Guidebook We encourage you to complete your DCOM setup with this step. Integrators frequently establish OPC communication and don’t spend the necessary time to secure the computers again. This can lead to catastrophic results if network security is compromised due to a virus, worm, malicious intent, or simply unauthorized “experimentation” by well-meaning coworkers. For more detail information, please refer to the OPC Training Institute: http://www.opcti.
Cellular Networks New Push Architecture for GPRS Networks Push Architecture is a mobile centric solution. Service providers such as web portals and e-mail servers use a fixed domain name. Clients such as mobile phones get information from these service providers by “pushing” the connection request to the Web and e-mail servers, and when a connection is established, the communication is bi-directional.
2009 Industrial Wireless Guidebook Benefits of Using Active GPRS I/O Moxa’s W5340 Active GPRS I/O devices come equipped with 4 analog inputs, 8 software configurable DI/ Os, and 2 relay outputs. In addition, the built-in GPRS communication, front-end intelligence, and data logging function give users the advantage of a highly integrated solution. The W5340 also features a 3-in-1 serial port (RS-232/422/485) for connecting field serial devices such as instruments or meters.
Creating Excellence Since 1987 About Moxa For more than twenty years, industrial systems integrators have relied on Moxa products in major device networking installations around the world. Moxa offers industrial-grade solutions backed by an excellent warranty and highly-specialized technical support for a diverse range of applications, including connecting PLCs to a wireless control network, transmitting temperature signals over long distances, and automating device control monitoring at remote locations.
