Endress+Hauser PROline prosonic flow 93 Ex-Dokumentation Zu Den Betriebsanleitungen Seite 43

PROline Prosonic Flow 93 PROFIBUS DP/PA
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Endress+Hauser
Setting the terminators (only by PROFIBUS DP)
Since mismatches in the impedance result in signal reflections on the line and can thus
lead to communication errors, it is important to terminate the lines properly.
Warning:
Risk of electric shock. Exposed components carry dangerous voltages. Make sure that
the power supply is switched off before you remove the cover of the electronics com-
partment.
The terminator switches are located on the I/O board.
• For baud rates of up to 1.5 MBaud, terminate the last transmitter on the bus by setting
the terminator switch SW 1 to: ON – ON – ON – ON.
• If the device is to be operated at over 1.5 Mbaud, you can tap the supply voltage for
an external terminator from terminals 24 (GND) and 25 (+5 V) (this terminator must be
in conformity with the requirements of the II2G standards).
Fig. 7: Setting the terminators (PROFIBUS DP)
A = Factory setting
B = Setting on the last transmitter
A
SW 1
ON
O N
OFF
O N
O N
O N
1 2 3 4
1 2 3 4
1 2 3 4
1 3 4
2
+5V
390 Ω 220 Ω 390 Ω
<
B
SW 1
ON
OFF
+5V
390 Ω
220 Ω 390 Ω
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