Image Processing Reference
In-Depth Information
FIGURE . Industrial automation devices with embedded WISA-POWER and WISA-COM technologies (left
side) and necessary infrastructure (right side).
m to
Cell dimensions which can be covered with the WPU power supply devices are 
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m respectively  m to close to  m in a single cell arrangement (without vertical loop
conductors inside).
Integrated into industrial IP products, including filtering on the device side, the fieldbus timing
uncertainty, and the handling delays on the base station side of a field bus master, the performance
stays within the specified limit.
The base station interface normally is a fieldbus, which adds additional latency. The base stations
also support over its built-in user interface a special configurable mapping mode, which can map
signals, e.g., of wireless sensors directly to other WISA devices with outputs. In that mode, very
simple latency measurements can be done, without being delayed by the bus interfaces.
Measurements published in Ref. [] show for the mapping mode a delay statistics with values
between  and  ms increasing in a coexistence setup with  WLAN networks to max.  ms for a few
telegrams out of  million measured. hese latency measurements were always for two acknowledged
WISA telegrams indicating that WISA works with latencies of typically  ms (.- ms).
The machine shown in Figure . has been in continuous shift operation since . In total,
several WISA applications with several hundred devices have been monitored over several years.
Therefore, up to date roughly  million device hours have been accumulated, giving a very good
feedbackoftheachievedreliabilityinproduction.hemainlessonslearnedwereonmechanical
issues (usability of housing and connector).
Applications with up to  independently rotating nodes in one machine (cable winding machine,
Karlskrona, Sweden) have been installed in  with up to four colocated base stations. All the
sensors are in cable drums which continuously move in a ferrous wheel type cage arrangement with
multidimensional movement. Several more of such machines are installed or planned.
A further challenging application where the real-time properties are mission critical is automotive
stamping. The delays of the wireless system have to be within the mechanical limits of the press,
otherwise drastic failures could occur. he wireless devices are installed in the press tools which are
frequently exchanged, so also fast start-up and reconnection times are an issue here. A WISA device
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