Modbus - Val Controls IHP24-A 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 • Limfjordsvej 3 • DK-6715 Esbjerg N • Tel. +45 7547 0600
DHW-UM-002
Revision: 3
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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