
ABB
ARC GUARD SYSTEM™ – CSU-2LV/2MV INSTALLATION AND MAINTENANCE GUIDE
41
6.4.4
Termination
For the best quality of data transfer, Modbus should be
terminated correctly.
The following figure shows the Modbus installation:
6.4.4.1
Termination resistors
A 120Ω resistor is added in parallel with the CSU-2 B+ and
A- terminals if it is installed as the first or last device on
the network. For this purpose, there are double terminals
for +(B) and -(A) connections.
6.4.4.2
Pull-up / pull-down resistors
When the Modbus network is not being actively driven
by a device, the bus line is in an undefined state. Bias
resistors should then be used to obtain a defined voltage
potential on the data lines. The bias resistors act for data
line B (D1) as pull-up resistors against 5V and for data line
A (D0) as pull-down resistors against GND.
The following devices usually have built-in bias resistors:
• Modbus masters
• Gateways
• Repeaters
Figure 29
Modbus termination
1SFC170020M0201
Slave 1
D
R
Master
D
R
Slave n
D
R
LT
LT
Balanced Pair
D1
5 V
Pull Up
Pull Down
D0
Common
06
Содержание CSU-2LV
Страница 2: ......
Страница 4: ......
Страница 6: ......
Страница 8: ......
Страница 12: ......
Страница 17: ...ABB ARC GUARD SYSTEM CSU 2LV 2MV INSTALLATION AND MAINTENANCE GUIDE 17 03 ...
Страница 18: ......
Страница 29: ...ABB ARC GUARD SYSTEM CSU 2LV 2MV INSTALLATION AND MAINTENANCE GUIDE 29 04 ...
Страница 30: ......
Страница 38: ......
Страница 66: ...66 ABB ARC GUARD SYSTEM CSU 2LV 2MV INSTALLATION AND MAINTENANCE GUIDE 06 ...
Страница 67: ...ABB ARC GUARD SYSTEM CSU 2LV 2MV INSTALLATION AND MAINTENANCE GUIDE 67 07 7 Maintenance 68 7 1 Introduction ...
Страница 69: ...ABB ARC GUARD SYSTEM CSU 2LV 2MV INSTALLATION AND MAINTENANCE GUIDE 69 07 ...
Страница 70: ......
Страница 75: ...ABB ARC GUARD SYSTEM CSU 2LV 2MV INSTALLATION AND MAINTENANCE GUIDE 75 08 ...
Страница 76: ......
Страница 83: ...ABB ARC GUARD SYSTEM CSU 2LV 2MV INSTALLATION AND MAINTENANCE GUIDE 83 09 ...