KSB CalioTherm Pro 25 Installation & Operating Manual page 31

Parameter
Protocol
Data format
Modbus address
5 Installation at Site
Description/value
Modbus RTU standard
▪ 8 data bits
▪ Parity EVEN / ODD / NONE
▪ 1 stop bit
ID #1 to #247 selectable
(ID #17 = factory setting)
ü The mains voltage at the site has been verified against the data on the name
plate.
ü The pump set has been de-energised and secured against unintentional start-up.
ü The wiring diagram is available.
1. Unscrew the cable glands (IPX4D).
2. Undo and store the 2 screws of the cover of the terminal wiring compartment.
3. Remove the cover of the terminal wiring compartment.
4. Knock out and remove the closing disc of the required cable gland with a
suitable tool (e.g. screwdriver).
5. Wire a suitable bus cable to the terminal pair of the three-piece Modbus
terminal and connect it to earth.
ð The terminals are suitable for a core cross-section of up to 1.5 mm
6. Fit the cover of the terminal wiring compartment. Fasten it with the 2 screws.
7. Tighten the cable glands (IPX4D).
Connection to the Modbus master
Connect all pump sets to a Modbus master. The Modbus master controls the bus
communication and sends telegrams to the connected pump sets. All pump sets are
slaves and only respond to the Modbus master. The pump sets do not send telegrams
by themselves. Each pump set is assigned its own unique address at the time of
commissioning.
Use a Modbus network cable or a cable with a defined impedance (e.g. Ethernet
cable) to prevent signal losses in the electric cable. System-specific signal losses occur,
for example, in the event of a failure of communication between Modbus master and
pump set.
1. Remove the cover of the terminal wiring compartment.
2. Connect a suitable Modbus network cable to terminals D+ and D- of the three-
piece Modbus terminal. Terminal 0 V is connected to earth at the pump end.
E.g. for connecting the bus cable shield.
Terminating the Modbus data line (hardware)
Terminate both ends of the Modbus network cable with a 120 Ω resistor. Enable both
DIP switches for this purpose.
The impedance of the Modbus network cable used corresponds to the terminating
resistor.
Example:
Terminating resistor = 120 Ω
Impedance of network cable = 120 Ω
CalioTherm Pro
2
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