KROHNE MFC 300 Modbus - Manual (Page 4)

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TECHNICAL DATA
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MFC 300
www.krohne.com 11/2009 - 4000744801 - AD Modbus MFC 300 R01 en
Technical data
2.1 General technical data
2.2 Technical data of the Modbus interface (acc. to EIA standards)
Interface RS485, galvanically isolated
Baud rate 1200, 2400, 4800, 9600, 19200, 38400, 57600 or 115200
Protocol Modbus RTU (available as a separate document on request)
Maximum participants on bus 32 per line, master included (may be extended by repeaters)
Coding NRZ bit coding
Address range Modbus: 1...247
Transmission procedure Half duplex, asynchronous
Bus access Master / slave
Cable Screened twisted pair
Distances Maximum 1.2 km / 3937 ft without repeater (dependant on
baud rate and cable specifications)
Kind of signal transmission Differential, 2-wire topology
Maximum number of
transmitter/receivers
32
Voltage range on converter input -7...+12 V
Maximum voltage on converter output 5 V
Minimum voltage on driver output, max.
load
U
diff
> 1.5 V
Maximum input current (off state) -20...+20 μA
Receiver input voltage -7...+12 V
Sensitivity of the receiver -200...+200 mV
Receiver input resistance > 12 kΩ
Short circuit current < 250 mA
Termination / polarization resistors
(if activated by the jumpers X5/X6)
120 Ω / 560 Ω
.book Page 4 Tuesday, November 24, 2009 1:48 PM