Kippzonen COMBILOG Data Logger Instrukcja Użytkownika Pobierz pdf (Strona 93)

Only signal leads A and B (and Shield) are absolutely obligat-

ory for a (shielded) connection. All others can be installed to-

gether with these signal leads if required.

10.6 Bus Termination

In order to avoid signal reflections on the bus, each bus seg-

ment has to be blanked off at its physical beginning and at its

end with the characteristic impedance. For this purpose, a ter-

minating resistor Rt is installed between the bus leads A and B.

In addition to that the bus lead A is connected via a pull-down

resistor Rd to ground (Data Ground) and the bus lead B is con-

nected via a pull-up resistor Ru to potential (VP). These resist-

ors provide a defined quiescent potential in case there is no

data transmission on the bus. This quiescent potential is level

high.

Figure 10.5 Bus termination

Note: The numbers in brackets in figure 10.5 indicate the pin

number for the connection via the 9-channel D-sub miniature

plug.

Hardware Manual COMBILOG 1022

DGND

VP = +5V

Ru = 390

Ω

± 2%, min ¼ Watt

Rd = 390

Ω

± 2%, min ¼ Watt

Rt = 390

Ω

± 2%, min ¼ Watt

B (3)

A (8)

Profibus-

Bezeichnung

Combilog-

Klemmen-

bezeichnung

watt

reference

1 2 ... 88 89 90 91 92 93 94 95 96 97 98 ... 172 173

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Kippzonen COMBILOG Data Logger Instrukcja Użytkownika Strona 93