Modbus; Terminals; Electrical Specifications - Val Controls I 24-B Series Hardware Manual

2.2 Modbus

Modbus
2
1
A
B

2.2.1 Terminals

Modbus 1 (A)
2 (B)
3 (A)
4 (B)
Terminals 1 and 3 are connected inside the device. Terminals 2 and 4 are connected inside the
device.

2.2.2 Electrical specifications

Modbus
Interface
Termination resistor
Galvanic isolated
A maximum of 247 nodes can be connected on the same daisy chain bus.
Typical shielding of the RS485 bus cable is done on the master side of the cable.
Val Controls A/S • Sallingsundvej 5 • DK-6715 Esbjerg N • Tel. +45 7547 0600
DHW-UM-001
Revision: 6
3 4
B
A
RS485
No internal resistor.
External resistor can be applied across terminal 3 and 4.
Termination resistors must have the value of 120 Ohm.
vc@valcontrols.com • www.valcontrols.com
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