KROHNE IFC 100 Converter Modbus EN - Manual (Page 5)

CONNECTION IN BUS SYSTEMS
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IFC 100
www.krohne.com 08/2014 - 4001410101 - AD Modbus IFC 100 R01 en
Connection in bus systems
For proper operation of Modbus in half duplex mode in single or multi-drop communication, it is
recommended that a termination resistor is applied to both ends of the data line. The simplest
form of termination is line-to-line resistor across the differential input.
In RTU mode the Modus protocol requires quiet periods on the communications bus for
synchronisation. It is therefore important that the Modbus is not allowed to "float", i.e.
unreferenced to 0 V, as this could lead to spurious signals due to noise pick-up. It is therefore
necessary to employ biasing resistors at one point on the bus network, normally the "end".
.book Page 5 Monday, July 28, 2014 11:32 AM