Shuji Yamamoto1 Naoki Maeda1 Makoto Takeuchi1 Masaaki Yonezawa1
The innovation of wireless technology encourages application of wireless communications to industry. Industrial communication networks require strict features such as robustness, real-time responsiveness, and low power consumption. ISA100.11a, an international wireless communication standard for industry, is designed to realize these capabilities. Yokogawa has commercialized the world's first two wireless field instruments and a device for field wireless systems based on the ISA100.11a with huge potentials, excellent expandability, and high affinity with process control. This report introduces these three products.
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Figure 1 External View of ISA100.11a-based Products |
The innovation of wireless technology increases the use of wireless communication in the industry. The introduction of wireless communication to plants, however, requires strict features such as robustness, real-time responsiveness, and low power consumption. This has restricted the use of wireless communication to limited applications such as data logging and device status monitoring that does not require strict real-time responsiveness and data arrival reliability in communication. However, ISA100.11a, a wireless communication standard for industrial automation, which could realize such strict features was published in September 20091. In response to that, in June 2010 Yokogawa released the world's first two wireless field instruments and a device for field wireless systems based on the ISA100.11a. This report introduces the features and capabilities of these wireless instruments and a wireless device for field wireless systems.
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Figure 2 Correspondence to the ISA100.11a System |
Yokogawa has developed the following three products based on the ISA100.11a standard. Figure 1 shows the external view of these products.
The EJX B series is already certified by the ISA100 Wireless Compliance Institute (WCI). Other models will also undergo evaluation tests and be certified one by one.
Correspondence to ISA100.11a Standard
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Figure 3 Connection with CENTUM VP FCS |
Figure 2 shows the correspondence between the system specified by the ISA100.11a standard and the newly developed products.
The following four functions specified by the ISA100.11a are integrated in the YFGW710.
Building a System Using ISA100 Products
Figure 3 shows a typical connection with the field control station (FCS) of Yokogawa's distributed control system (DCS) CENTUM VP. The communication with the FCS utilizes Modbus/TCP, a Modbus protocolNote 1) implemented on top of the Ethernet TCP/IP protocol.
Since field wireless devices are equipped with built- in batteries and the communication with the upper system is wireless, wiring is not required. This makes it possible to reduce installation costs remarkably and facilitates new applications.
For details, please refer to the report entitled "Field Wireless Solution Based on the ISA100.11a to Innovate Instrumentation" in this special issue of Yokogawa Technical Reports.
The following describes the specifications and features common in the three newly developed products, and those of the individual products. Wireless Communication Features of ISA100-based Products The three newly developed products utilize the same wireless modules and have the same wireless communication features. Table 1 shows the major wireless specifications. The antennas of the EJX B series and YTA510 have the physically same design.
Table 1 Major Wireless Specifications Common in ISA100-based Products
Item | Description |
---|---|
Wireless standard | Compliant with the ISA100.11a (IEEE802.15.4) |
Frequency band | 2400-2483.5 MHz |
Communication data rate | 250 kbps |
RF Transmitter power | Max. 11.6 dBm (fixed) |
Wireless security | AES 128 bit codified*1 |
Antenna | +2 dBi Omni directional antenna |
*1: Common key encryption method developed as the Advanced Encryption Standard (AES) in the USA.
Battery Maintenance Procedure
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Figure 4 Battery Pack and Battery Replacing Procedure |
A new battery pack has been developed to enable replacement of the batteries in the field. This battery pack can be used for both the EJX B series differential pressure/ pressure transmitters and YTA510 temperature transmitter. Figure 4 shows the external view of the newly developed battery pack and the battery replacing procedure.
This procedure makes it possible to replace the battery pack in hazardous areas. In order to reuse the case, the battery pack is designed so that batteries inside can be taken out and replaced. Large-capacity lithium-thionyl chloride batteries that are general- use and readily available in the market were adopted.
Specifications and Features of EJX B Series Differential Pressure/Pressure Transmitters
The EJX B series inherits the features of the existing EJX series, such as the high reliability of the sensor, multi-sensing function, and enhanced self-diagnostic functions, as they are. A low-power consumption design was implemented in order to extend the life of the built-in batteries, while keeping the capabilities and functions of existing ones. Table 2 shows the major specifications of the EJX110B differential pressure transmitters.
Table 2 Major Specifications of EJX110B
Item | Description |
---|---|
Differential pressure accuracy | ± 0.04% |
Static pressure accuracy | ± 0.2% (for absolute pressure output) |
Long-term stability (zero-point) | ± 0.1% of URL*1 /10 year |
Data update interval | 1 to 3600 sec selectable |
Battery life | 4 years under the following typical operating conditions. Update interval: 10 seconds Device role: IO mode*2 Ambient temperature: 23°C LCD display: off |
Operating temperature range | -40 to 85°C |
Process temperature range | -40 to 120°C |
Operating humidity range | 0 to 100% RH |
Degrees of Protection | IEC 60529 IP66/67, NEMA 4X |
Explosion protection specification | Intrinsic safety (TIIS*3, IECEx, ATEX, FM, CSA) |
Weight | 4.9 kg (without battery pack, mounting brackets, and process connector) |
*1: Upper Range Limit,
*2: Basic function only without router function
*3: To be certified
To meet various applications, Yokogawa has lined up a variety of transmitter models, such as a differential pressure transmitter, pressure transmitter, absolute pressure transmitter, flange mounted differential pressure transmitter, screw- mount pressure transmitter, and diaphragm sealed differential pressure/pressure transmitter.
Specifications and Features of YTA510 Temperature Transmitter
The YTA510 is a high performance temperature transmitter that accepts various signals: inputs from IEC standard thermocouples (eight types including Type K, E, and J are applicable), inputs from IEC or other standard resistance temperature detectors (RTD) (three types including Pt100 are applicable), DC current corresponding to resistance, and DC milivolts. It converts them to values corresponding to the measured values and sends to the upper system via wireless communication. Furthermore, it sends and receives diagnostic information of devices and settings parameters via wireless communication. The robust design and stable characteristics ensure stable field operations as well as a two-wire YTA series does. Table 3 shows the major specifications.
Table 3 Major Specifications of YTA510
Item | Description |
---|---|
Sensor input | Major RTDs, thermocouples, DC mVs, OHMs |
Accuracy | Pt100 ± 0.3°C, Type K ± 0.6°C, etc. |
Reference junction accuracy | ± 0.5°C |
Data update interval | 1 to 3600 sec selectable |
Battery life | 6 years under the following typical operating conditions. Update interval: 10 seconds Device role: IO mode*1 Ambient temperature: 23°C LCD display: off |
Operating temperature range | -40 to 85°C |
Operating humidity range | 0 to 100% RH |
Degrees of protection | IEC 60529 IP66/67, NEMA 4X |
Explosion protection specification | Intrinsic safety (TIIS*2, IECEx, ATEX, FM, CSA) |
Weight | 2.8 kg (without battery pack, mounting brackets, and process connector) |
*1: Basic function only without router function,
*2: To be certified
A power-saving design was implemented for the YTA510 in order to extend the life of the built-in batteries which are required for wireless communication. Furthermore, since the temperature transmitter is required to be installed near the measurement location, it was designed so that the input wire length can be minimized. In addition, the temperature conversion circuit was newly designed to optimize the wireless operations.
Specifications and Features of YFGW710 Integrated Gateway
The following describes the features of the YFGW710. Table 4 shows the major specifications of the YFGW710 Integrated Gateway.
Table 4 Major Specifications of YFGW710
Item | Description |
---|---|
Rated voltage | 24 VDC |
Voltage range | 10.0 to 26.4 VDC |
Power consumption | Max. about 10 W |
Operating temperature range | -40 to 60°C |
Operating humidity range | 0 to 100% RH |
Degrees of protection | IEC 60529 IP66, NEMA 4X |
Explosion protection specification | Non-incendive (FM, CAS), Type n (IECEx, CENELEC, ATEX), Non-sparking Type n (TIIS*1) |
Upper communication protocol | Modbus/TCP |
Upper communication interface | 100BASE-TX (RJ-45 connector), 100BASE-FX (SC connector) |
Antenna connector type | N-type jack; antenna impedance 50 W |
Maximum number of connected wireless field instruments | Maximum 50 units (update interval 5 seconds) Maximum 10 units (update interval 1 second) |
*1: To be certified
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Figure 5 Communication Distances and Packet Error Rates (Comparing Yokogawa's Models) |
The three newly developed products utilize wireless modules that have higher receive sensitivity than that of Yokogawa's existing wireless products in order to improve wireless communication performance. Increased receive sensitivity makes it possible to build a wireless communication infrastructure with higher performance and wider communication range in a plant environment where there is considerable radio reflection. Consequently, this helps to reduce the number of repeaters, extend the wireless communication range, and ensure communication stability in the plant environment. Figure 5 shows the experimental results of communication distances of the newly developed ISA100-based wireless products and Yokogawa's existing wireless products based on another standard. The communication distance of the ISA100-based products is approximately three times as long as that of the existing wireless products.
The extended communication range makes it possible to configure a wide star topology network that does not require hoppings (relaying between the wireless devices), which are required in the mesh topology network. A star topology network is superior in stability and real-time responsiveness which are required in the plant. In addition, eliminating the need for hopping means that no relaying communication is required, extending the life of the built-in batteries.
Yokogawa has released the world's first products based on the ISA100.11a standard: the EJX B series differential pressure/pressure transmitters, YTA510 temperature transmitter, and YFGW710 Field Wireless Integrated Gateway. Furthermore, in order to maximize the use of these products, Yokogawa is carrying out experiments in the field for various applications and accumulating the operation results of field wireless systems. Yokogawa is accumulating the experience and success stories in applications with a wide field area of the plant where especially wireless communication is effective; namely, at off-sites, in tank yards, coal storage yards, water discharge and intake facilities, oil wells, and the like.
Yokogawa plans to enhance the performance of these three models, deploy those technologies to other field instruments, and introduce or develop new technologies such as Wi-FiNote 2) communication that would improve the performance and convenience of wireless systems. At present, Yokogawa uses batteries to supply power to the field wireless instruments but plans to develop energy harvesting technology that captures energy from external sources such as sunlight, heat, vibrations, or electromagnetic waves to supply power to the field instruments.
Note 1) A communication protocol developed by Modicon Inc. (AEG Schneider Automation International S.A.S.) for PLC
Note 2) Abbreviation of Wireless Fidelity, indicating that the interconnectivity between the wireless LAN devices is certified by Wi-Fi Alliance.
The high performance wireless differential pressure transmitter EJX110B features a single crystal silicon resonant sensor and is suitable to measure liquid, gas, or steam flow as well as liquid level, density, and pressure.
Wireless diaphragm seals are used to prevent process medium from entering directly into the pressure-sensing assembly of the differential pressure and pressure transmitters, they are connected to the transmitter using capillaries filled with fill fluid.
The high performance wireless flange mounted differential pressure transmitter EJX210B features a single crystal silicon resonant sensor and is suitable to measure levels of densities of solidifying or precipitating liquids.
The high performance wireless pressure transmitter EJX310B features a single crystal silicon resonant sensor and are suitable to measure liquid, gas, or steam flow as well as liquid level, density, and pressure.
The high performance wireless guage pressure transmitter EJX430B features a single crystal silicon resonant sensor and are suitable to measure liquid, gas, or steam flow as well as liquid level, density, and pressure.
Wireless diaphragm seals are used to prevent process medium from entering directly into the pressure-sensing assembly of the differential pressure and pressure transmitters, they are connected to the transmitter using capillaries filled with fill fluid.
The high performance wireless absolute and gauge pressure transmitters EJX510B and EJX530B feature single crystal silicon resonant sensor and are suitable to measure liquid, gas, or steam pressure.
The high performance wireless absolute and gauge pressure transmitters EJX510B and EJX530B feature single crystal silicon resonant sensor and are suitable to measure liquid, gas, or steam pressure.
YFGW710 Field Wireless Integrated Gateway comply to the wireless communications standard ISA100.11a for industrial automation of International Society of Automation (ISA), and relays ISA100 Device data to the system via integrated backbone router. Single unit of YFGW710 has integrated functions of backbone router, system manager, security manage, and gateway.
The high performance temperature transmitter YTA510 accepts Thermocouple, RTD, ohms or DC mill volt inputs. The transmitters transmit not only process variables but also the setting parameters using wireless signal. The transmitters run on internal batteries, and the installation cost can be decreased since hard-wiring is not required. The communication is based on ISA100.11a protocol specifications.
Yokogawa delivers critical operational infrastructure for process automation. Our distributed control system (DCS) enables automation and control of industrial processes and enhanced business performance. Over 10,000 plants entrust Yokogawa DCS to deliver their production goals.
The accurate and stable measurement of process pressure with Yokogawa Pressure Transmitters supports the safe, reliable, and profitable operation of your plant.