WirelessHART with Pepperl+Fuchs
As a worldwide supplier for conventional intrinsic safety interface devices, Pepperl+Fuchs is one of the leading process automation companies offering solutions for communication between field devices and the DCS. Our comprehensive product portfolio, ranging from simple analog isolators via remote I/O systems up to complete field bus infrastructures, is designed especially for the needs of process automation. However these process measurement and control applications still require to be connected with wire: costly, time-consuming wiring, but this will soon change.
Pepperl+Fuchs is developing WirelessHART products. Functional prototypes were presented at ISA2006 in Houston.
The HART Field Communications Protocol is the global standard for smart process instrumentation. Seventy percent of all smart process measurement and control instruments installed worldwide each year use HART Communication and the global installed base of HART-enabled devices is the largest of all communication protocols at more than 20 million. WirelessHART extends the power of HART communication and offers huge benefits. The objective to is produce a wireless communication standard for process measurement and control applications.
It brings high-speed connectivity to HART field devices and enables the sharing of data between these devices not with a 4-20 mA loop, but 'over-the-air'. To bridge the distances in wide-spread facilities a flat mesh network is utilized. Each device acts not only as signal source, but also as repeater. Information is routed through the whole network until it reaches the base station as the final recipient. Pepperl+Fuchs was the only supplier featuring a WirelessHART multiplexer as a functioning prototype at ISA2006.
The uses of WirelessHART are similar to these of conventional HART:
- Parameterize of field devices
- Supervision of uncritical measurements and environmental values
- Asset management and optimizing
- Preventive maintenance
- Performance monitoring
- Energy management
These applications are a good introduction to wireless technologies since they do not demand hard requirements in terms of latency and transmission security. Therefore, the utilization of a mesh network in non critical applications is practical. The time delay caused by repeating the message is negligible compared to the low transmission rate of the conventional HART standard. After proving the capability of HART in conjunction with wireless technologies the next step would be simple, open-loop controls.
The concept of WirelessHART enables a seamless integration to the present HART infrastructure. Existing HART devices can be upgraded to enable the wireless communication. In the future all HART-capable devices could be designed wireless. 
The next step will generate devices which will be WirelessHART capable right from the start. 
Pepperl+Fuchs is currently developing two products:
Our WirelessHART multiplexer acts as a message coordinator for communication between the 
maintenance workstation PC and the HART devices, the core of each WirelessHART Network. The WirelessHART Multiplexer acts as a conventional HART Multiplexer on the DCS side to ensure integration in existing DCS. This was demonstrated at the ISA2006 with three DCS units. The communication with the field devices takes place via radio.
To upgrade the available field devices a WirelessHART adapter will be developed. This device is put into the 4-20 mA loop, extracts the HART signal and sends this over the air. Depending on application several upgrade options would be offered:
A loop-powered adapter. This allows simple integration to the existing control loop. The existing wiring will continue to be used for conventional signal transmission, WirelessHART will be transmitted through the adapter.
A battery-powered adapter. This option will supply the field device from a battery powered option. According to the selected duty cycle the field device is powered up, the measurement value is read and transmitted, and the field device is powered down again. This enables independent measurements.
