Additional information
8099_en_02
PHOENIX CONTACT
4-5
Single client
This mode merges the LAN termination device (computer, controller etc.) and the EPA so
that the rest of the network considers them to be a single device. For this, the EPA
represents itself via the wireless interface with the MAC address of the termination device.
In this way, each network device is able to communicate with the termination device at
maximum performance.
In addition, the connection has “layer 2 transparency” which means that it also transmits
protocols that are not using the TCP/IP protocol.
However, by using the MAC address only one single termination device can be connected
on the wired side of the EPA.
Multi client (default)
Multi-client mode can be used for most applications. The EPA can also use the MAC
address of a termination device and thus enable connections with layer 2 transparency to
this single device.
Additional devices on the wired side of the EPA can also be connected with layer 3
transparency and are therefore available for most applications on a TCP/IP basis.
As the multi-client mode provides a high performance it is recommended for most
applications.
(Multi) UDP tunnel
Depending on the protocol used it may be necessary to communicate with several devices
on the wired side of the EPA using layer 2 transparency. To do so, an EPA is used on either
side of the wireless connection. The EPA “packs” the incoming data packets into a UDP
packet and sends it to the other EPA. The other EPA then “unpacks” the UDP packet and
makes the original packet available again. This makes transmission of the packet
independent of the protocol used. Transmission can be performed via the internal wireless
module of the EPA or via any other existing (wireless) infrastructures.
The additional protocol data reduces the usable transmission speed when compared to the
other modes.
In the “multi UDP tunnel” operating mode, multiple tunnels can be defined. Typically, this
device is then the tunnel starting point on the LAN side of a larger WLAN network. The
WLAN wireless module of the EPA can be switched off for this purpose. Wireless
transmission is then via an available WLAN network.
The “UDP tunnel” operating mode is provided for tunnel end points which enable
communication with (mobile) termination devices on the mobile side via the EPA wireless
module.
4.3
PROFINET/PROFIsafe via WLAN
The PROFIBUS user organization has specified PROFIsafe for wireless transmission
paths. Positive concept assessments have also been obtained from the BGIA (Professional
Institute for Safety at Work) and TÜV (German Technical Inspectorate). The version of the
PROFIsafe profile (version 2.4) describes the marginal conditions for the functionally safe
transmission of data via WLAN and Bluetooth. In particular, security aspects for the
configuration of wireless components and for safeguarding cyclic data exchange are
specified. The FL WLAN EPA meets these requirements when it is operated in operating
