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ProSMS 8
INSTALLATION MANUAL
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6.1
MODBUS interface
The MODBUS interface is not intended to be accessible to the user during operation.
The MODBUS interface is protected by a three-stage built-in circuit which meets IEC 61643-
21 class D1/C1/C2/C3. There is no need to install additional external DATA protection devices.
Fig. 6-1: Example of master at beginning of bus
Fig. 6-2: Example of master in the middle of bus
•
Use one twisted pair for A and B signals
•
Connect both wires of the remaining twisted pair to GND MODBUS Terminal
•
If a cable has more than two twisted pairs, connect all unused pairs to GND MODBUS
terminals at each ProSMS unit. For optimal data communication, do not leave these floating
•
The last unit in the chain must be terminated with a 120 ohm resistor
•
GND Modbus wires (Data signal common potential) should be grounded once at the master
unit
•
Cable shield should be grounded at each combiner box or at least at the Master unit with all
shields in all combiner boxes connected together
•
The Master unit must be terminated with a 120 ohm resistor if it is at the beginning of the bus
CAUTION
VOLTAGE
DANGER
WARNING
NOTICE
CAUTION
VOLTAGE
DANGER
WARNING
NOTICE
(Insert #2)
(Insert #3)
(Insert #2)
(Insert #3)
Содержание ProSMS 8
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