PROFIBUS Manual
Depending on whether DP/PA links or DP/PA segment couplers are used, the rules for installing an MBP segment remain identical. Unlike RS 485 installation, with MBP there is a free choice of topology: linear bus, stub lines or tree structure. Stub lines are a popular assembly method with MBP because individual field devices are linked with connecting boxes.
Connection boxes for the connection of devices (E+H)
The length of stub lines in an MBP network depends on the number of stub lines. The table shows recommended lengths for stub lines. Please note the additional restrictions for an intrinsically safe installation.
Number of stub lines |
Maximum length of a stub line |
Maximum length of a stub line for EExi installation |
|---|---|---|
25 to 32 |
1 m |
1 m |
19 to 24 |
30 m |
30 m |
15 to 18 |
60 m |
30 m |
13 to 14 |
90 m |
30 m |
1 to 12 |
120 m |
30 m |
Field devices can be connected and removed, even when the bus is powered up, without affecting other field devices. Just be careful not to short circuit the cable. With a short circuit, all field devices on a single segment will be without power.
