Endress+Hauser PROline prosonic flow 93 II3G Ex-Dokumentation Zu Den Betriebsanleitungen Seite 34

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14
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 and a waiting period of 10 minutes is observed, before
you remove the cover of the electronics compartment.
The terminator switches are located on the I/O board.
1. Remove the screws and open the housing cover (1).
2. Remove the screws securing the electronics module (2). Then push up electronics
module and pull it as far as possible out of the wall-mount housing.
3. Unplug ribbon cable connector (3) of the display module.
4. Remove the cover (4) from the electronics compartment by loosening the screws.
5. Removing the I/O board:
Insert a thin pin into the opening provided (5) and pull the board out of the holder.
6. Use a pointed object to adjust the positions of the miniature switches on the
I/O board.
7. Installation is the reverse of the removal procedure.
8. When mounting, ensure that the Ingress Protection is maintained.
1
2
5
Fig. 5: Setting the terminators (PROFIBUS-DP)
A = Factory setting
B = Setting on the last transmitter
In addition, pay attention to the following points:
• 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 II3G standards).
PROline Prosonic Flow 93 PROFIBUS-DP/-PA
3 4
6
A
SW 1
ON
O N OFF
O N
O N
O N
1 1 2 3 3 4 4
2
1 2 3 4
1 2 3 4
+5V
390 Ω 220 Ω
B
SW 1
ON
OFF
+5V
390 Ω 220 Ω 390 Ω
390 Ω
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