KROHNE UFC 300 Wiring diagram

Signal converter for ultrasonic flowmeters
Description of Modbus interface
Description of Modbus interfaceDescription of Modbus interface
Description of Modbus interface
Electronic revision: ER 4.0._
Modbus version: 2.1.1_
UFC 300
UFC 300UFC 300
UFC 300 Supplementary Instructions
Supplementary InstructionsSupplementary Instructions
Supplementary Instructions
© KROHNE 03/2019 - 4007044501 - AD UFC 300 V2 Modbus R01 en

CONTENTS
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UFC 300
1 General information 4
1.1 Scope of the document..................................................................................................... 4
1.2 Scope of delivery............................................................................................................... 4
1.3 Modbus protocol interface ............................................................................................... 4
2 Technical data 5
2.1 General technical data .....................................................................................................5
2.2 Technical data of the Modbus interface (acc. to EIA/TIA 485 standard).......................... 5
3 Electrical connections 6
3.1 Modbus connection........................................................................................................... 6
3.2 Connection to Modbus bus ............................................................................................... 6
4 Establish RS485 connection 7
5 Modbus protocol 8
5.1 RTU frame format............................................................................................................. 8
5.2 Data representation ......................................................................................................... 9
5.2.1 8-bit values.............................................................................................................................. 9
5.2.2 16-bit values............................................................................................................................ 9
5.2.3 32-bit values............................................................................................................................ 9
5.2.4 64-bit values.......................................................................................................................... 10
5.3 Modbus Register Addresses .......................................................................................... 11
5.4 Supported Function Codes ............................................................................................. 11
5.5 Error messages.............................................................................................................. 12
5.6 Device identification ....................................................................................................... 13
5.7 Diagnostics ..................................................................................................................... 13
5.8 Parameters..................................................................................................................... 14
5.8.1 Device Control....................................................................................................................... 14
5.8.2 Device Status......................................................................................................................... 14
5.8.3 Measurement Values ............................................................................................................ 15
5.8.4 Measurement Status compliant with NAMUR NE 107......................................................... 16
5.8.5 Auxiliary Values..................................................................................................................... 17
5.8.6 Totaliser ................................................................................................................................ 18
5.8.7 Zero Calibration .................................................................................................................... 21
5.8.8 Process Input Parameters.................................................................................................... 21
5.8.9 Install Parameters ................................................................................................................ 23
5.8.10 Modbus RS485 Communication Settings ........................................................................... 26
5.8.11 NAMUR NE 107 Variable Status Group(s)........................................................................... 27
6 Application sequences 28
6.1 Saving and restoring the configuration setting ............................................................. 28
6.2 Zero Calibration.............................................................................................................. 29

CONTENTS
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UFC 300
7 Troubleshooting 30
7.1 No response to Modbus requests .................................................................................. 30
7.2 Communication errors ................................................................................................... 30
7.3 Responding with exception "Illegal Function"............................................................... 30
7.4 Responding with exception "Illegal Data Address" ....................................................... 31
7.5 Responding with exception "Illegal Data Value"............................................................ 31
8 Appendix 32
8.1 NAMUR NE 107 Status Group(s) .................................................................................... 32
8.2 NAMUR NE 107 status signals ....................................................................................... 33
8.3 Supported Modbus function codes................................................................................. 33
8.4 Number format............................................................................................................... 36
8.5 Glossary .......................................................................................................................... 36
9 Notes 37

1 GENERAL INFORMATION
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1.1 Scope of the document
These instructions are supplementary to the signal converter handbook. For all other data, use
the relevant chapters of the handbook. If you do not have this document, please contact the
nearest office or download them from the manufacturer's internet site.
1.2 Scope of delivery
The information in this supplementary manual only contains the data applicable to Modbus
communication.
The technical data in the handbook shall be valid in its current version, provided that it is not
rendered invalid or replaced by this supplement.
1.3 Modbus protocol interface
The Modbus interface to the signal converter is implemented in the Modbus RTU
communications protocol and is done in accordance with the specification and requirements of
the "Modbus Protocol Specification V1.1b".
The physical electrical parameters of the Modbus specification are defined by the EIA/TIA 485
(RS485) standard and the "Modbus over Serial Line - Specification and Implementation Guide
V1.02".
Both specifications can be obtained on the official website of the Modbus organisation:
http://www.modbus.org

TECHNICAL DATA 2
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2.1 General technical data
2.2 Technical data of the Modbus interface (acc. to EIA/TIA 485 standard)
Interface RS485, galvanically isolated
Baud rate 1200, 2400, 4800, 9600, 19200, 38400, 57600 or 115200 bps
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 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)
Table 2-1: General technical data
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 5V
Minimum voltage on driver output, max.
load U
diff
>1.5V
Maximum input current (off state) -20...+20 μA
Receiver input voltage -7...+12 V
Sensitivity of the receiver -200...+200 mV
Receiver input resistance >12kΩ
Short circuit current < 250 mA
Termination / polarization resistors
(if activated by factory) 120 Ω/ 560 Ω
Table 2-2: Technical data of the Modbus interface (acc. to EIA/TIA 485 standard)