5 Installation at Site
30 of 68
Calio
1157.821/04-EN
Example:
Terminating resistor = 120 Ω
Wave impedance of network cable = 120 Ω
C
O
M
R
U
N
D
U
A
L
0
-1
0
V
L
Vin
0 V
R
1
2
D-
D+
H
0 V
0 V
0 V
a1
a2
a3
a4
a5
Fig. 14:
Terminal wiring diagram for the Modbus data line
a
Data line connections
a1
External 0 - 10 V
a2
External start/stop
a3
Terminating resistor for Modbus cable (DIP switches)
a4
Modbus or KSB ServiceTool
a5
Dual-pump configuration
The terminating resistor is enabled when the corresponding pump-integrated DIP
switch in the terminal wiring compartment next to the Modbus terminal pair is
enabled. See illustration.
Table 9:
Key to the terminal codes
Terminal code
Description
RS485
Modbus
D-
A-
D0
D+
B+
D1
0 V
COM
COM
Table 10:
Settings of Modbus terminating resistors
Position of DIP switches 1 and 2
Status
ON
Modbus terminating resistor enabled
OFF
Modbus terminating resistor disabled
NOTE
The two DIP switches 1 and 2 must both be set to the same status.
Fig. 15:
Illustration of terminals
