ABB ProcessMaster FEM630 Operating Instructions Manual page 50

50
F EM63 0 | E L EC TR OM AG N E T I C FLOWM E T E R | O I/F E M6 3 0-EN RE V. A
6 . . .Electrical connections
. . .Digital communication
Limits and rules when using ABB fieldbus accessories
Figure 59 Bus cable length depends on the transmission rate
Pro PROFIBUS Line
(Line = Starts at DP Master and goes to last DP/PA Slave)
• Approximately 4 to 8 DP segments through the repeater
(see repeater data sheets)
• Recommended DP transfer rate 500 to 1500 kBit/s
• The slowest DP node determines the transfer rate of the
DP line
• Number of PROFIBUS DP and PA nodes ≤ 126 (addresses
0 to 125)
Per PROFIBUS DP segment
Number of DP nodes ≤ 32
• (Node = Devices with / without PROFIBUS address)
• Bus termination required at the beginning and end of
each DP segment!
• Trunk cable length (LT) see diagram (length dependent
on transfer rate)
• Cable length of at least 1 m between two DP nodes at ≥
1500 kBit/s!
• Spur cable length (LS), at ≤ 1500 kBit/s: LS ≤ 10", at >
1500 kBit/s: LS = 0.0"!
• At 1500 kBit/s and ABB DP cable type A:
– Sum of all spur cable lengths (LS) ≤ 21.6 ft, trunk cable
length (LT) > 21.6 ft, total length = LT+ (Σ L
maximum 22 DP nodes (= 21.6 ft / (10" + 2" spare))
) ≤ 656 ft,
S