How to connect the databus to LAN without a Gateway? ...using a PDU!
In the figure you see a small databus-ring with only four
devices connected to a LAN: a Classic PDU and PDU with
ethernet port. The device connected to the LAN must
have an ethernet port and be in "BRIDGE" mode. All
other devices should be in "Hybrid" mode. The BRIDGED
device takes over the function of the Schleifenbauer
Gateway.
You can connect numerous of Schleifenbauer devices to
the device which is in BRIDGE mode: PDUs and DPM3's (=
3 channel energy meter) as well as Classic PDUs and
DPM27 (= 27 channel energy meter). The sequence of
devices does not affect the performance of the
databus-ring. But, the more devices you place in the
databus-ring, the slower data transmission will be. The
scheme shows that you can use different kind of
Schleifenbauer devices in a ring which makes the system
easily scalable to your needs. It is advised to close your
databus ring. So it is best to connect the last device in
the databus to the device which is in BRIDGE-mode. In a
closed databus ring you can reach all connected devices
via IN and OUT databus ports (clockwise and
anti-clockwise).
Advantages: (1) when only using devices with ethernet
port: only the device in BRIDGE mode uses one
IP-address. (2) you can select any device connected to
your LAN as long as you place it in BRIDGE mode, (3)
investment in a Schleifenbauer Gateway is not
necessary, (4) the system is easily scalable
Disadvantage: MySQL and SMTP can not be used
Databus communication is 0,2 seconds per
query (e.g. input measures block). Therefore
we advice to make rings with a maximum of 50
devices which means that querying each
device once will last appr. 10 seconds
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