Looking at the large number of possible applications and configurations, we generally differentiate between two application types.

With the first type, the reason is that, according to estimates made by the HART Communication Foundation (HCF), approx. 85% of the more than 30 million HART devices are used in an environment in which only the 4 ... 20 mA interface is used on the system side, but not the HART interface of the device. Generally, data on the device can only be read on site. This is a great disadvantage, especially for devices with functions for self-diagnostics. This is referred to as "stranded diagnostics".

In these cases, a WirelessHART adapter can offer assistance. Connected to the 4 ... 20 mA loop, it allows for wireless and central access to the device. It does not affect older process control systems which continues to receive the measured value using the 4 ... 20 mA-loop.

Central access takes place via a diagnostics station with SIMATIC PDM.

The most important advantages:

• Increases the availability of the system
• Increases system transparency
• Cost reductions through a predictive instead of a preventive maintenance concept
• Shorter distances to be covered in larger plants as result of central access to field instrumentation

In the second type of application, the 4 ... 20 mA loop is omitted; all data as well as the process values measured and the diagnostic information are transmitted wirelessly, e.g. to a process control system.

The most important advantages:

• No planning and installation of data cables, resulting in sometimes significant cost reductions.
• Increased transparency in the plant through additional installation of measuring points, which was previously uneconomical.
• Process optimization using flexible, temporary and low-cost measuring points with wireless communication.
• Utilization of proven devices by using adapters
• Coverage also of longer distances using the meshed WirelessHART network.