261Gx, 261Ax
| IM/261Gx/Ax-EN Rev. 08 19
Change from two to one column
Fig. 11: "Point-to-point" communication mode
1 Pressure transmitter | 2 Possible connecting points for a modem between A and B | 3 Power supply unit | 4 FSK modem
Fig. 12: "FSK bus" communication mode
1 FSK bus | 2 Supply module with HART isolation | 3 FSK modem
Change from one to two columns
5.6
Connecting cable
Communication between the transmitter and PC or laptop is
only possible if the cabling meets the following requirements:
The minimum wire diameter depends on the line length.
Line lengths up to 1,500 m: 0.51 mm
Line lengths above 1,500 m: 0.81 mm
The maximum line length is limited.
Dual-core cable: 3,000 m
Multi-core cable: 1,500 m
The actual possible line length of the electrical circuit depends
on the total capacitance and total line resistance, and can be
estimated using the following formula:
C
C
RxC
x
L
f
1000
6
10
65
L = Line length in m
R = Total line resistance in Ω (ohms)
C = Line capacitance in pF/m
C
f
= Capacitance of the devices located in the circuit in pF
Avoid routing cables with other electrical cables (with inductive
load, etc.) or near large electrical equipment.
M10693
p
I + FSK
A
U
B
U
S
+
+
+
–
–
#
R
2600T
RS 232C
4
1
2
3
M10694
RS 232C
p
I + FSK
A
U
B
U
S
+
+
+
#
R
2600T
4 & 20 mA
p
I + FSK
A
U
B
U
S
+
+
+
#
R
2600T
4 & 20 mA
1
1
3
2
2
