ABB COPA-XE, Instruction Bulletin

Page: 58 / 64

52
Electromagnetic Flowmeter
COPA-XE / MAG-XE
9.3.8 Supplementary Information for
Connecting Profibus PA
Profibus PA Protocol
Transmission format
per IEC 1158-2
Transmission speed 31.25 KByte/s
Protocol per EN 50170
Ident-No. 6668 HEX
Cyclical (output variables “out” and “Out _Total”)
The variable “OUT” contains the present measurement value in
engineering units (%, l/s, m3/h...) and the corresponding
status.
The variable “Out_Total” contains the present totalizer value in
engineering units (m3, l...) and the corresponding status.
Acyclical
• Flowmeter primary size
(“NOMINAL_SIZE”)
• Instantaneous flowrate units
(“FLOWRATE_UNITS”)
• Self test on/off
(“SELF_CHECKING”)
• Flow direction normal/inverse
(“FLOW_DIRECTION”)
• Excitation frequency
(“SAMPLE_RATE”)
• Low flow cutoff value in %
(“LOW_FLOW_CUTOFF”)
• and additional data, see separate Data Link Description for
COPA/MAG-XE)
The stored data are maintained during power interruptions.
Cable
A 2-conductor twisted shielded Cu cable per EN 50170 Type A
is recommended
Conductor area (nominal):
0.8 mm
2
(AWG 18)
Loop resistance (DC) 44
Ω
/km
Characteristic impedance at 31.25 kHz 100
Ω
+/-20 %
Wave attenuation at 39 kHz 3 dB/km
Capacitive unsymmetry 2 nF/km
Max. cable length 1900 m for use with standard Power Supply
Type IV (Segment Coupler) in non-Intrinsically Safe Design
(U = 24 V, Imax = 500 mA, Pmax = 12 W)
Tap lead: Max. 30 - 60 m from tee or from subdistributor.
No. of participants: Max. 32 instruments on a single segment,
maximum 126 in total
Bus topology: Tree and/or linear structure
Bus termination:Passive at both ends of the main bus
(RC-Element R = 100
Ω
, C = 1 µF)
Isolation in-/outputs: There is no galvanic isolation between the
current output (ter/-) and the Profibus PA (terminals
PA+/PA-)!
Profibus-DP
Supply Power
Profibus-PA
93.75-156.25 Kbit/s (H2-Bus)
Transmission speed is a func-
tion of the segment coupler
31.25 Kbit/s IEC 1158-2 (H1-Bus)
R=
100
Ω
C=
1
µ
F
+
-
I
≤
15 mA I
≤
15 mA I
≤
15 mA
I
≤
15 mA
COPA-XE
MAG-XE COPA-XE
MAG-XE COPA-XE
MAG-XE COPA-XE
MAG-XE
PA+ PA- PA+ PA- PA+ PA- PA+ PA-
Segment
Coupler
incl. Supply
and Bus
Termination
Fig. 42 Profibus