KROHNE MFC-400 User Manual

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Page 1

Supplementary instructions

MFC 400

MFC 400MFC 400

Supplementary instructions Supplementary instructions

Signal converter for mass flowmeters

Description of Modbus interface

Description of Modbus interfaceDescription of Modbus interface

Electronic Revision: ER 1.0.3_ Modbus version 2.1.0_

Page 2

CONTENTS

MFC 400

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 standards) .............................. 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.............................................................................................................. 11

5.6 Device identification ....................................................................................................... 12

5.7 Diagnostics ..................................................................................................................... 13

5.8 Parameters..................................................................................................................... 13

5.8.1 Device Control....................................................................................................................... 14

5.8.2 Device Status......................................................................................................................... 15

5.8.3 Measurement values ............................................................................................................ 16

5.8.4 Measurement Status compliant with NAMUR NE 107 ......................................................... 16

5.8.5 Auxiliary Values..................................................................................................................... 17

5.8.6 Totaliser ................................................................................................................................ 17

5.8.7 Zero Calibration .................................................................................................................... 20

5.8.8 Density Calibration Coefficients ........................................................................................... 21

5.8.9 Density Configuration ........................................................................................................... 21

5.8.10 Filters .................................................................................................................................. 22

5.8.11 System Control.................................................................................................................... 22

5.8.12 Calibration Coefficients ...................................................................................................... 23

5.8.13 Modbus RS485 Communication Settings ........................................................................... 24

5.8.14 NAMUR NE 107 Variable Event Group(s)............................................................................ 25

5.8.15 Concentration 1................................................................................................................... 26

5.8.16 Concentration 2................................................................................................................... 27

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MFC 400

CONTENTS

6 Application sequences 28

6.1 Saving and restoring the configuration setting ............................................................. 28

6.2 Zero calibration .............................................................................................................. 29

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 Event 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

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1 GENERAL INFORMATION

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".

MFC 400

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

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MFC 400

TECHNICAL DATA 2

2.1 General technical data

Interface RS485, galvanically isolated

Baud rate 1200, 2400, 3600, 4800, 9600, 19200, 38400, 57600 or

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

115200 bps

baud rate and cable specifications)

2.2 Technical data of the Modbus interface (acc. to EIA/TIA standards)

Kind of signal transmission Differential, 2-wire topology

Maximum number of transmitter/receivers

Voltage range on converter input -7...+12 V

Maximum voltage on converter output 5V

Minimum voltage on driver output, max. load

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)

>1.5V

diff

120 Ω / 560 Ω

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3 ELECTRICAL CONNECTIONS

3.1 Modbus connection

The signal converter is hooked up onto the bus using terminals C and D:

Terminals Description

D- Signal A (D 0)

D Signal B (D 1)

C- Common 0 V

C Not connected

Terminals A and B of the signal converter are dependant on the options selected at order. Refer to the standard handbook of the signal converter for connection details.

3.2 Connection to Modbus bus

The signal converter is designed to be connected as a slave device onto the 2-wire bus implementation of the Modbus serial physical layer definition.

MFC 400

In addition to the D0 and D1 signal lines the bus MUST ground reference point for the data signals.

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.

MUST include a "Common" signal line to act as a

MUSTMUST

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MFC 400

ESTABLISH RS485 CONNECTION 4

To establish a RS485 connection with the signal converter, prepare the master device with the appropriate default settings or use custom parameters specified via display of the signal converter.

The Modbus RS485 settings can be found in the menu C6.8 of the display. The following parameters can be configured:

Parameter Legal values Default values Display Fct. No.

Slave address 1...247 1 C6.8.1

"Baude rate" 1200, 2400, 3600, 4800, 9600,

Parity Even, Odd, No Even Parity C6.8.3

Data format Big Endian, Little Endian Big Endian C6.8.4

Transmission delay

Stop Bits 1 Stop Bit, 2 Stop Bits 1 Stop Bit C6.8.6

19200, 38400, 57600, 115200 bps

0...0.04 [s] 0s C6.8.5

19200 bps C6.8.2

These settings can be changed via Modbus too. For further information refer to

Communication Settings

on page 24.

Modbus RS485

All devices connected to the bus, must have the same baud rate.

INFORMATION!

It is of great importance to ensure at the time of the procedure of devices addressing, that there are not two devices with the same address. In such a case, an abnormal behaviour of the whole serial bus can occur. It is then impossible for the master to communicate with all present slaves on the bus.

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5 MODBUS PROTOCOL

5.1 RTU frame format

Using RTU (Remote Terminal Unit) format, data is transmitted as 8 bit binary characters. There are no special characters to determine the start and end of a message frame. Synchronization is achieved by a minimum silent period of at least 3.5 character times before the start of each frame transmission and a maximum silent period of 1.5 character times between characters in the same frame.

The format of the query and response frames vary slightly depending upon the function code. The basic form is outlined below.

Command function Frame format Description

MFC 400

Silent period 3.5 x T All transmissions must be preceded by a minimum silent

Slave address 8bits This is a single byte slave address which is transmitted

Function code 8bits This is an eight bit code in the range of 1...255 although

Number of points or data bytes when required

8 bit byte count 16 bit address

n×8bits Number of points:

period of 3.5 x T, where T is the transmission time of a single character. This can be calculated from the baud rate, e.g. T = 572 µs at 19.2 kbps.

first and must be in the range of 1...247. Address 0 is reserved for a broadcast address which all slaves should recognise, and therefore requires no response.

only 126 functions exist as the codes 129...255 represent an error condition. An error condition occurs when the addressed slave does not accept the command, in which case it responds with the function code + 128, i.e. with its msb set to 1.

Register start address:Register start address: data to be returned, this field will contain the 16 bit start address of the register (or data) to be returned. Note that the signal converter uses protocol addresses. Therefore the register address listed is the actual number required in the Modbus command.

E.g:

E.g: to access input register 30006, the register start

E.g:E.g: address is 30006 = 0x7536.

Byte count:

Byte count: In general this is only present in frames that

Byte count:Byte count: are transferring data, and has a value equal to the number of bytes contained in the data field. The data field is limited to a maximum of 250 bytes.

Number of points: for a query command that requires data

Number of points:Number of points: to be returned, this field will contain the number of registers to be returned regardless of their bit size.

Data bytes:

Data bytes: contains the data requested. The signal

Data bytes:Data bytes: converter can use Big Endian format (MSB first) or Little Endian format (LSB first).

CRC 16 bits This field contains a 16 bit CRC which is calculated on all

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the data bits of the message bytes.

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MFC 400

5.2 Data representation

There are two data types used to transmit information on a Modbus data bus, the "Bit" and the "Register". The "Bit" represents a single binary state, whether as an output or an input condition. The "Register" is a 16-bit integer transmitted as two 8-bit characters. Using multiple "Registers" the Modbus interface can transmit higher accuracy values such as "Floating Point" and "Double Precision Floating Point" numbers.

"Bit" variables are packed into a byte containing 8 bit, so each character, sent or received, can contain up to 8 "Bit" variables. The master and slave devices use only as many 8 bit data characters as are required to transmit the information. Any unused bits in the data characters are ignored. The bit that is requested by the start address is transmitted in the LSB at bit 0. The next "Bit" value is transmitted in the next bit (bit 1). This continues until the last bit location (bit 7) of the LSB is reached. The next "Bit" value is then transmitted in the next data byte (LSB+1/MSB) at bit 0. This continues until all of the requested values have been transmitted. Any unused bits in the MSB are filled out with "0"s.

For simple single register variables the MSB of the register is transmitted first, with the LSB following immediately after. However, for variables that require multiple registers, i.e. the "Floating Point" and "Double Precision Floating Point" variables, the transmission order can be selected in the RS485 settings. By default, those values will be transmitted in Big Endian.

MODBUS PROTOCOL 5

5.2.1 8-bit values

N 0x00 Byte

5.2.2 16-bit values

N MSB LSB

5.2.3 32-bit values

Little Endian

N LSB + 1 LSB

N + 1 MSB LSB + 2

Big Endian

N MSB LSB + 2

N + 1 LSB + 1 LSB

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5 MODBUS PROTOCOL

Float (single precision, IEEE 754)

MSB LSB + 1 LSB + 1 LSB

SEEEEEEE EMMMMMMM MMMMMMMM MMMMMMMM

With S = sign, E = exponent, M = mantissa/fraction

5.2.4 64-bit values

Little Endian

N LSB + 1 LSB

N + 1 LSB + 3 LSB + 2

N + 2 LSB + 5 LSB + 4

N + 3 MSB LSB + 6

MFC 400

Big Endian

N MSB LSB + 6

N + 1 LSB + 5 LSB + 4

N + 2 LSB + 3 LSB + 2

N + 3 LSB + 1 LSB

Double (double precision, IEEE 754)

MSB

MSB LSB + 6

MSBMSB

SEEEEEEE EEEEMMMM MMMMMMMM MMMMMMMM

LSB + 3

LSB + 3 LSB + 2

LSB + 3LSB + 3

MMMMMMMM MMMMMMMM MMMMMMMM MMMMMMMM

LSB + 6 LSB + 5

LSB + 6LSB + 6

LSB + 2 LSB + 1

LSB + 2LSB + 2

LSB + 5 LSB + 4

LSB + 5LSB + 5

LSB + 1 LSB

LSB + 1LSB + 1

LSB + 4

LSB + 4LSB + 4

LSB

LSBLSB

With S = sign, E = exponent, M = mantissa/fraction

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MFC 400

5.3 Modbus Register Addresses

The signal converter supports four types of data references, which are associated to a range of Modbus registers.

Address range Primary tables Access rights

0...9999 Coils read + write

10000...19999 Discrete Inputs read

20000...39999 Input Registers read

40000...65535 Holding Registers read + write

INFORMATION!

•

Sometimes register numbers are asked for. The register numbers can be calculated by adding a 1 to the register address.

•

Some systems cannot use addresses above 9999. For these systems there is the possibility to use the listed addresses but

- for Input Registers omit the leading 3 of 3xxxx;

- for Holding Registers omit the leading 4 of 4xxxx.

MODBUS PROTOCOL 5

5.4 Supported Function Codes

Function code Name

dec hex

01 01 Read Single Coil

02 02 Read Descrete Inputs

03 03 Read Holding Register

04 04 Read Input Register

05 05 Write Single Coil

08 08 Diagnostics

16 10 Write Multiple Register

43 2B Encapsulated Interface Transport

For detailed information about the telegrams structure of all function codes refer to

Modbus function codes

on page 33.

5.5 Error messages

When the signal converter detects an error in the requests, received in a properly formatted telegram, it will respond with an error message. The error message response telegram is formatted as follows:

Supported

Address Function Code Error Code CRC Lo CRC Hi

The msb (most significant bit) of the requested function code is set (add 0d128 / 0x80) in the reponse telegram to indicate an error has been detected. For example, if an error were detected in a function 1 request, then the returned function code would be 0x81 (0d129).

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5 MODBUS PROTOCOL

The single data character in the response telegram will indicate the type of error detected. These are as follows:

MFC 400

Error

Name Meaning

Code

01 ILLEGAL FUNCTION The requested function code is not supported or not valid due to the

02 ILLEGAL DATA

03 ILLEGAL DATA VALUE The requested data is invalid for the register being written.

04 SLAVE DEVICE

06 SLAVE DEVICE BUSY The slave is unable to process the requested command because a

ADDRESS

FAILURE

Errors due to communications faults (CRC errors, Parity errors etc.) are logged but no response is returned because the data in the received telegram is deemed unreliable. The master system can read the error logs by using the diagnostics command (for details on Function Code 0x08 refer to

Diagnostics

on page 13).

5.6 Device identification

Retrieve all of the identification information from the signal converter.

Modbus Function Code "Encapsulated Interface Transport" (0x2B).

current settings of the device.

The register requested is not valid or the quantity of requested registers hits invalid registers.

An unrecoverable error occurred while the slave was attempting to perform the requested action.

long-duration command is in progress. The master should retransmit the message later.

Modbus Encapsulated Interface (MEI) type (0x0E).

Category Object IdObject name Type Content

Basic 0x00 VendorName 16 byte ASCII String KROHNE

0x01 ProductCode 10 byte ASCII String CG number; order code for the

0x02 MajorMinorRevision 7 byte ASCII String Electronic Revision number

Regular 0x03 Vendor URL 32 byte ASCII String www.krohne.com

0x04 ProductName 16 byte ASCII String MFC400

0x05 ModelName 16 byte ASCII String Modbus

0x06 UserApplicationName 16 byte ASCII String User tag, displayed on the

signal converter assembly

header of the local screen

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MFC 400

5.7 Diagnostics

This command function permits the user to perform one of several diagnostics operations, such as retrieving the error and event logs. For further details on this command function, refer to the Modbus Application Protocol Specification V1.1b.

Modbus Function Code "Diagnostics" (0x08)

Sub function code Name

dec hex

00 00 Return Query Data

01 01 Restart Communication Option

04 04 Force Listen Only Mode

10 0A Clear Counters

11 0B Return Bus Message Count

12 0C Return Bus Communication Error Count

13 0D Return Bus Exception Count

14 0E Return Slave Message Count

15 0F Return Slave No Response Count

18 12 Return Bus Character Overrun Count

MODBUS PROTOCOL 5

5.8 Parameters

The functions of the Modbus interface are arranged in groups of thematically coherent parameters.

Large gaps have been left between these groups of data types in order to permit expansion of the signal converter interface and compatibility with further high performance signal converters.

Some registers are protected by a custody transfer lock for use when the signal converter is used in custody transfer applications. These registers are indicated by the symbol.

The configuration of the signal converter can be changed via Modbus Holding Registers. Writing data to those registers does not take effect immediately. In order to apply the new configuration it is necessary to perform "Apply Changes". Parameters that require "Apply Changes" are

indicated by the symbol. Changes that are not applied can be discarded via "Discard Changes" (details on page 14). For further information refer to

Application sequences

on page 28.

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5 MODBUS PROTOCOL

5.8.1 Device Control

The "Device Control" offers some basic functionality to operate with the signal converter. Therefore, the Modbus interface provides five coils that can be accessed via Modbus Function Code "Write Single Coil" (0x05).

MFC 400

Write a coil to value 1

value 1 (ON) to initiate the action.

value 1value 1

Modbus Function Code "Write Single Coil" (0x05)

Coil

Name Description Display

Address

1000

10001000 (0x03E8)

1001

10011001 (0x03E9)

1002

10021002 (0x03EA)

1003

10031003 (0x03EB)

1004

10041004 (0x03EC)

Restart Device Restart entire signal converter D2.2.1

Reset Errors Clears the system error flags A3.1

Apply Changes Apply latest changes of configuration -

Discard Changes Discard all of the configuration changes made since the last "Apply

Reset to Factory Data

Changes"

Resets the signal converter to factory configuration C6.6.3

The flow sensor can be switched between three modes. Use the following Modbus register to request a change of the operation mode. The actual operation mode can be read via Modbus register 39000 (details on page 15).

Modbus Function Codes "Read Holding Registers" (0x03) and "Write Multiple Registers" (0x10)

Fct. No.

Holding Register

51000

5100051000 (0XC738)

Name Description Type No. of

registers

Operation Mode

Set the actual operation mode of the flow sensor

Byte 1 1 = Stop Mode

Values Display

Fct. No.

A.9 3 = Measure Mode 5 = Standby Mode

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MFC 400

5.8.2 Device Status

Modbus Function Codes "Read Discrete Inputs" (0x02)

MODBUS PROTOCOL 5

Discrete

Name Description Type No. of

Inputs

10000

1000010000 (0x2710)

10001

1000110001 (0x2711)

Status of Custody Transfer Lock

Are Changes Made?

Indicates if custody transfer lock is active or no

Indicates if there are unsaved changes. "Apply Changes" to save them, "Discard Changes" to work with previous settings

Modbus Function Codes "Read Input Registers" (0x04)

Input

Name Type No. of

39000

3900039000 (0x9858)

39002

3900239002 (0x985A)

39004

3900439004 (0x985C)

39100

3910039100 (0x98BC)

Actual Operation Mode Long 2 1 = Stop

Device Operation Time Float 2 [s] B2.1

NE 107 Status Groups Long 2 For further information refer to

NE 107 Device Status Byte 1 Bit 7 = Failure (F)

registers

Values

registers

Bit 1 0 = unlocked

Bit 1 0 = no changes made

1 = locked

1 = unsaved changes detected

Values / Units Display

Fct. No.

2 = Startup 3 = Measuring 5 = Standby

NAMUR NE 107 Event Group(s)

on page 32.

Bit 6 = reserved Bit 5 = Out of Specification (S) Bit 4 = Function Check (C) Bit 3 = reserved Bit 2 = Maintenance required (M) Bit 1 = reserved Bit 0 = Information (I)

B2.16

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5 MODBUS PROTOCOL

5.8.3 Measurement values

Modbus Function Codes "Read Input Registers" (0x04)

MFC 400

Input Register

30000

3000030000 (0x7530)

30002

3000230002 (0x7532)

30004

3000430004 (0x7534)

30006

3000630006 (0x7536)

30008

3000830008 (0x7538)

30010

3001030010 (0x753A)

30012

3001230012 (0x753C)

30014

3001430014 (0x753E)

30016

3001630016 (0x7540)

1 Only available with option "concentration measurement"

Name Type No. of

Units Display

registers

Flow Velocity Float 2 [m/s] B2.5

Volume Flow Float 2 [m³/s] B2.4

Mass Flow Float 2 [kg/s] B2.3

Temperature Float 2 [K] B2.7

Density Float 2 [kg/m³] B2.6

Concentration 1 Value 1 Float 2 [Brix], [% Mass], [Baume 144],

Concentration 2 Value1 Float 2 -

Concentration 1 Flow 1 Float 2 [m³/s] or [kg/s] -

Concentration 2 Flow 1 Float 2 -

[Baume 145], [% NaOH], [Plato], [% Volume], [API], [% Alcohol by mass], [% Alcohol by volume]

5.8.4 Measurement Status compliant with NAMUR NE 107

Fct. No.

Modbus Function Codes "Read Input Registers" (0x04)

Input

Name Type No. of

30500

3050030500 (0x7724)

30501

3050130501 (0x7725)

30502

3050230502 (0x7726)

30503

3050330503 (0x7727)

30504

3050430504 (0x7728)

30505

3050530505 (0x7729)

30506

3050630506 (0x772A)

30507

3050730507 (0x772B)

30508

3050830508 (0x772C)

NE 107 Status of Flow Velocity Byte 1 Bit 7 = Failure (F)

NE 107 Status of Volume Flow Byte 1

NE 107 Status of Mass Flow Byte 1

NE 107 Status of Temperature Byte 1

NE 107 Status of Density Byte 1

NE 107 Status of Conc. 1 value Byte 1

NE 107 Status of Conc. 2 value Byte 1

NE 107 Status of Conc. 1 flow Byte 1

NE 107 Status of Conc. 2 flow Byte 1

Values

registers

Bit 6 = reserved Bit 5 = Out of Specification (S) Bit 4 = Function Check (C) Bit 3 = Initial Value Bit 2 = Maintenance required (M) Bit 1 = Value is too large and limited Bit 0 = Value is too small and limited

If none of these bits is set, there is no status message.

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MFC 400

5.8.5 Auxiliary Values

Modbus Function Codes "Read Input Registers" (0x04)

MODBUS PROTOCOL 5

Input Register

31000

3100031000 (0x7918)

31002

3100231002 (0x791A)

31004

3100431004 (0x791C)

31006

3100631006 (0x791E)

31008

3100831008 (0x7920)

31010

3101031010 (0x7922)

31012

3101231012 (0x7924)

31014

3101431014 (0x7926)

Name Type No. of

Units Display

registers

Drive Level Float 2 [%] B2.11

Sensor A Level Float 2 [%] B2.12

Sensor B Level Float 2 [%] B2.13

Strain 1 Float 2 [Ω] B2.8

Strain 2 Float 2 [Ω] B2.9

Tube Frequency Float 2 [Hz] B2.10

2 Phase Signal Float 2 - B2.14

SE PCB Temperature Float 2 [K] B2.15

5.8.6 Totaliser

Modbus Function Codes "Read Coils" (0x01) and "Write Single Coil" (0x05)

Coil Address

Name Function Action Values Display

Fct. No.

3000

30003000 (0x0BB8)

3001

30013001 (0x0BB9)

3002

30023002 (0x0BBA)

3003

30033003 (0x0BBB)

3004

30043004 (0x0BBC)

3005

30053005 (0x0BBD)

1 Only available in signal converters with "modular carrier"

Totaliser 1 Start / Stop Write 0 = stop totaliser

Status Read 0 = totaliser stopped

Totaliser 2 Start / Stop Write 0 = stop totaliser

Status Read 0 = totaliser stopped

Totaliser 3 1 Start / Stop Write 0 = stop totaliser

Status Read 0 = totaliser stopped

Totaliser 1 Reset set totaliser value

to zero

Totaliser 2 Reset set totaliser value

to zero

Totaliser 3 Reset 1set totaliser value

to zero

Write 1 = reset totaliser C4.1.6

Write 1 = reset totaliser C4.2.6

Write 1 = reset totaliser C4.3.6

1 = start totaliser

1 = totaliser running

1 = start totaliser

1 = totaliser running

1 = start totaliser

1 = totaliser running

C4.1.8 /

C4.1.9

C4.2.8 /

C4.2.9

C4.3.8 /

C4.3.9

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5 MODBUS PROTOCOL

Modbus Function Code "Read Input Registers" (0x04)

MFC 400

Input Register

32000

3200032000 (0x7D00)

32004

3200432004 (0x7D04)

32008

3200832008 (0x7D08)

32100

3210032100 (0x7D64)

32102

3210232102 (0x7D66)

32104

3210432104 (0x7D68)

1 Only available in signal converters with "modular carrier"

Name Type No. of

Units

registers

Totaliser 1 value (double precision) Double 4 [m³] or [kg]

Totaliser 2 value (double precision) Double 4

Totaliser 3 value (double precision) 1 Double 4

Totaliser 1 value (single precision) Float 2

Totaliser 2 value (single precision) Float 2

Totaliser 3 value (single precision) 1 Float 2

Modbus Function Codes "Read Holding Registers" (0x03) and "Write Multiple Registers" (0x10)

Holding Register

40000

4000040000 (0x9C40)

40001

4000140001 (0x9C41)

40002

4000240002 (0x9C42)

40003

4000340003 (0x9C43)

40004

4000440004 (0x9C44)

40005

4000540005 (0x9C45)

1 Only available in signal converters with "modular carrier" 2 Only available with option "concentration measurement"

Name Action Type No. of

Values Display

registers

Totaliser 1 Function Byte 1 0 = Off

Measurement Byte 1 1 = Volume Flow

Totaliser 2 Function Byte 1 0 = Off

Measurement Byte 1 1 = Volume Flow

Totaliser 3

Function Byte 1 0 = Off

Measurement Byte 1 1 = Volume Flow

1 = Absolute total 2 = Increment 3 = Decrement

2 = Mass Flow 14 = Conc. 1 Mass Flow 2 15 = Conc. 1 Volume Flow 2 16 = Conc. 2 Mass Flow 2 17 = Conc. 2 Volume Flow 2

1 = Absolute total 2 = Increment 3 = Decrement

2 = Mass Flow 14 = Conc. 1 Mass Flow 2 15 = Conc. 1 Volume Flow 2 16 = Conc. 2 Mass Flow 2 17 = Conc. 2 Volume Flow 2

1 = Absolute total 2 = Increment 3 = Decrement

2 = Mass Flow 14 = Conc. 1 Mass Flow 2 15 = Conc. 1 Volume Flow 2 16 = Conc. 2 Mass Flow 2 17 = Conc. 2 Volume Flow 2

Fct. No.

C4.1.1

C4.1.2

C4.2.1

C4.2.2

C4.3.1

C4.3.2

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MFC 400

MODBUS PROTOCOL 5

Modbus Function Codes "Read Holding Registers" (0x03) and "Write Multiple Registers" (0x10)

Holding

Name Action Type No. of

40500

4050040500 (0x9E34)

40502

4050240502 (0x9E36)

40504

4050440504 (0x9E38)

40506

4050640506 (0x9E3A)

40508

4050840508 (0x9E3C)

40510

4051040510 (0x9E3E)

40512

4051240512 (0x9E40)

40514

4051440514 (0x9E42)

40516

4051640516 (0x9E44)

40518

4051840518 (0x9E46)

40520

4052040520 (0x9E48)

40522

4052240522 (0x9E4A)

1 Only available in signal converters with "modular carrier"

Totaliser 1 Low Flow Cut-Off

Totaliser 2 Low Flow Cut-Off

Totaliser 3

Value

Time Constant 0...100 [s] C4.1.4

Set or Read Value [m³] or [kg] C4.1.7

Preset [m³] or [kg] C4.1.5

Value

Time Constant 0...100 [s] C4.2.4

Set or Read Value [m³] or [kg] C4.2.7

Preset [m³] or [kg] C4.2.5

Low Flow Cut-Off Value

Time Constant 0...100 [s] C4.3.4

Set or Read Value [m³] or [kg] C4.3.7

Preset [m³] or [kg] C4.3.5

Float 2 [m³/s] or [kg/s] C4.1.3

Float 2 [m³/s] or [kg/s] C4.2.3

Float 2 [m³/s] or [kg/s] C4.3.3

registers

Units Display

Fct. No.

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5 MODBUS PROTOCOL

5.8.7 Zero Calibration

Due to process and installation variations that cannot be accounted for by factory calibration, it is always good practice to perform regular zero calibrations on the sensor to ensure the accuracy of the results.

The Coils and Registers below are required to perform a zero calibration. For further information refer to

Zero calibration

Modbus Function Codes "Read Coils" (0x01) and "Write Single Coil" (0x05)

on page 29.

MFC 400

Coil

Name Function Action Values Display

Address

2000

20002000 (0x07D0)

Zero Calibration Control

Start Write 1 = start zero calibration C1.1.1

Status Read 0 = zero calibration not running /

complete 1 = zero calibration in progress

Modbus Function Code "Read Input Registers" (0x04)

Input Register

20000

2000020000 (0x4E20)

20001

2000120001 (0x4E21)

Name Type No. of

Values

registers

Zero Calibration Result Byte 1 0 = success

Zero Calibration new "Zero Flow Offset"

Float 2 -

1 = fail – sensor not measuring 2 = fail – zero too high

Modbus Function Codes "Read Holding Registers" (0x03) and "Write Multiple Registers" (0x10)

Holding

Name Type No. of

46000

4600046000 (0xB3B0)

Zero Calibration Value Float 2

Fct. No.

registers

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MFC 400

5.8.8 Density Calibration Coefficients

Modbus Function Code "Read Input Registers" (0x04)

MODBUS PROTOCOL 5

Input

Name Type No. of registers Display

33000

3300033000 (0x80E8)

33002

3300233002 (0x80EA)

33004

3300433004 (0x80EC)

33006

3300633006 (0x80EE)

33008

3300833008 (0x80F0)

33010

3301033010 (0x80F2)

33500

3350033500 (0x82DC)

33501

3350133501 (0x82DD)

DCF2 Float 2 C1.8.2

DCF3 Float 2 C1.8.3

DCF4 Float 2 C1.8.4

DCF6 Float 2 C1.8.6

DCF7 Float 2 C1.8.7

DCF8 Float 2 C1.8.8

DCF1 Byte 1 C1.8.1

DCF5 Byte 1 C1.8.5

5.8.9 Density Configuration

Modbus Function Codes "Read Holding Registers" (0x03) and "Write Multiple Registers" (0x10)

Holding Register

Name Type No. of

registers

Values Display

Fct. No.

D1.2.2

D1.2.3

D1.2.4

D1.2.6

D1.2.7

D1.2.8

D1.2.1

D1.2.5

Fct. No.

43000

4300043000 (0xA7F8)

43500

4350043500 (0xA9EC)

43502

4350243502 (0xA9EE)

43504

4350443504 (0xA9F0)

43506

4350643506 (0xA9F2)

43508

4350843508 (0xA9F4)

43510

4351043510 (0xA9F6)

43512

4351243512 (0xA9F8)

1 Only if Density Mode = Fixed 2 Only if Density Mode = Referred 3 Only if Density Mode = Standard

Density Mode Byte 1 0 = Actual

Fixed Density Value

Density Referred Temperature

Referred Density Slope

Standard Density Temperature

Standard Density k0

Standard Density k1

Standard Density k2

1 = Fixed

C1.2.2

2 = Referred 3 = Standard

Float 2 0.08...5000 [kg/m³] C1.2.3

Float 2 28.15...773.15 [K] C1.2.3

Float 2 0...65 C1.2.4

Float 2 28.15...773.15 [K] C1.2.5

Float 2 0...5000 C1.2.6

Float 2 -100...100 C1.2.7

Float 2 -10...10 C1.2.8

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5 MODBUS PROTOCOL

5.8.10 Filters

Modbus Function Codes "Read Holding Registers" (0x03) and "Write Multiple Registers" (0x10)

MFC 400

Holding Register

45000

4500045000 (0xAFC8)

45500

4550045500 (0xB1BC)

45502

4550245502 (0xB1BE)

45504

4550445504 (0xB1C0)

45506

4550645506 (0xB1C2)

45508

4550845508 (0xB1C4)

45510

4551045510 (0xB1C6)

45512

4551245512 (0xB1C8)

Name Type No. of

Values Display

registers

Flow Direction Byte 1 1 = Forwards

2 Phase Threshold Float 2 0...1000 C1.5.3

Pipe Diameter Float 2 0.001...0.5 [m] C1.3.1

User Flow Offset Float 2 -32...32 C1.1.2

Low Flow Cut-Off Float 2 0...10 [%] C1.3.4

Pressure Suppression Time Float 2 0...20 [s] C1.3.2

Pressure Suppression Cut-Off Float 2 0...10 [%] C1.3.3

Flow Correction Float 2 -10...10 [%] C1.1.4

2 = Backwards

5.8.11 System Control

Modbus Function Codes "Read Holding Registers" (0x03) and "Write Multiple Registers" (0x10)

Fct. No.

C1.3.1

Holding Register

44000

4400044000 (0xABE0)

44001

4400144001 (0xABE1)

44500

4450044500 (0xADD4)

44502

4450244502 (0xADD6)

44504

4450444504 (0xADD8)

44506

4450644506 (0xADDA)

Name Type No. of

registers

Function Byte 1 1 = Off / No Action

Condition Byte 1 0 = Density

Density Min. Limit Float 2 0.08...5000 [kg/m³] C1.4.3

Density Max. Limit Float 2 0.08...5000 [kg/m³] C1.4.4

Temperature Min. Limit Float 2 73...773 [K] C1.4.3

Temperature Max. Limit Float 2 73...773 [K] C1.4.4

Values Display

Fct. No.

C1.4.1

2 = Flow=0

C1.4.2

1 = Temperature

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MFC 400

5.8.12 Calibration Coefficients

Modbus Function Code "Read Input Registers" (0x04)

MODBUS PROTOCOL 5

Input Register

34000

3400034000 (0x84D0)

34002

3400234002 (0x84D2)

34004

3400434004 (0x84D4)

34006

3400634006 (0x84D6)

34008

3400834008 (0x84D8)

34010

3401034010 (0x84DA)

34012

3401234012 (0x84DC)

34014

3401434014 (0x84DE)

34016

3401634016 (0x84E0)

34018

3401834018 (0x84E2)

34020

3402034020 (0x84E4)

34022

3402234022 (0x84E6)

34024

3402434024 (0x84E8)

34026

3402634026 (0x84EA)

34028

3402834028 (0x84EC)

34030

3403034030 (0x84EE)

34032

3403234032 (0x84F0)

34034

3403434034 (0x84F2)

34036

3403634036 (0x84F4)

34038

3403834038 (0x84F6)

34040

3404034040 (0x84F8)

34042

3404234042 (0x84FA)

34044

3404434044 (0x84FC)

Name Type No. of registers Display

Fct. No.

CF1 Float 2 D1.1.1

CF2 Float 2 D1.1.2

CF3 Float 2 D1.1.3

CF4 Float 2 D1.1.4

CF5 Float 2 D1.1.5

CF6 Float 2 D1.1.6

CF7 Float 2 D1.1.7

CF8 Float 2 D1.1.8

CF11 Float 2 D1.1.9

CF12 Float 2 D1.1.10

CF13 Float 2 D1.1.11

CF14 Float 2 D1.1.12

CF15 Float 2 D1.1.13

CF16 Float 2 D1.1.14

CF17 Float 2 D1.1.15

CF18 Float 2 D1.1.16

CF19 Float 2 D1.1.17

CF20 Float 2 D1.1.18

CF21 Float 2 D1.1.19

CF22 Float 2 D1.1.20

CF23 Float 2 D1.1.21

CF24 Float 2 D1.1.22

CF26 Float 2 D1.1.24

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5 MODBUS PROTOCOL

Modbus Function Code "Read Input Registers" (0x04)

MFC 400

Input

Name Type No. of registers Display

34046

3404634046 (0x84FE)

34500

3450034500 (0x86C4)

CF27 Float 2 D1.1.25

CF25 Byte 1 D1.1.23

5.8.13 Modbus RS485 Communication Settings

Modbus Function Codes "Read Holding Registers" (0x03) and "Write Multiple Registers" (0x10)

Holding Register

50000

5000050000 (0xC350)

50002

5000250002 (0xC352)

50004

5000450004 (0xC354)

50005

5000550005 (0xC355)

50006

5000650006 (0xC356)

Name Description Type No. of

Values Display

registers

Baud rate Baud rate for the RS485

Transmission Delay

Slave Address Modbus Slave Address Byte 1 1 (default)...247 C6.8.1

Parity Parity for the RS485 Modbus

Modbus Communication in [bps]

Select transmission delay between Modbus request and Modbus response in [ms]

Communication

Switch Register Format Little Endian or Big Endian

Long 2 1200, 2400, 3600,

4800, 9600, 19200 (default), 38400, 57600, 115200

Float 2 0 (default)...0.04 C6.8.5

Byte 1 0 = Even (default)

1 = Odd 3 = Off

Byte 1 0 = Little Endian

1 = Big Endian (default)

Fct. No.

C6.8.2

C6.8.3

C6.8.4

50007

5000750007 (0xC357)

Stop Bits Number of Stop Bits Byte 1 1 = 1 Stop Bit

(default) 2 = 2 Stop Bits

C6.8.6

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MFC 400

MODBUS PROTOCOL 5

5.8.14 NAMUR NE 107 Variable Event Group(s)

The following eight event groups can be mapped to any status signal.

For further information refer to section "Status messages and diagnostic information" in the signal converter standard manual.

Modbus Function Codes "Read Holding Registers" (0x03) and "Write Multiple Registers" (0x10)

Holding Register

52016

5201652016 (0xCB30)

52017

5201752017 (0xCB31)

52018

5201852018 (0xCB32)

52019

5201952019 (0xCB33)

52020

5202052020 (0xCB34)

52021

5202152021 (0xCB35)

52022

5202252022 (0xCB36)

52023

5202352023 (0xCB37)

Description Status Group Type No. of

registers

Status Signal of Event Group 15

Status Signal of Event Group 14

Status Signal of Event Group 13

Status Signal of Event Group 12

Status Signal of Event Group 11

Status Signal of Event Group 10

Status Signal of Event Group 9

Status Signal of Event Group 8

Proc: Current Input Byte 1 128

Electr: IO Connection Byte 1 32

Proc: Signal Search Byte 1 128

Proc: 2 Phase Flow Byte 1 32

Proc: Signal Low Byte 1 32

Config: Totaliser Byte 1 32

Proc: System Control Byte 1 1

Electr: Power Failure Byte 1 32

Default Value Display

Fct. No.

C1.5.9 Failure (F)

C1.5.14 Out Of Specification (S)

C1.5.8 Failure (F)

C1.5.10 Out Of Specification (S)

C1.5.7 Out Of Specification (S)

C1.5.12 Out Of Specification (S)

C1.5.11 Information (I)

C1.5.13 Out Of Specification (S)

Legal values for those registers:

• 128: Failure (F)

• 32: Out Of Specification (S)

• 16: Function Check (C)

• 4: Maintenance Request (M)

• 1: Information (I)

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5 MODBUS PROTOCOL

5.8.15 Concentration 1

INFORMATION!

Only available with option "concentration measurement".

Modbus Function Codes "Read Holding Registers" (0x03) and "Write Multiple Registers" (0x10)

MFC 400

Holding Register

42000

4200042000 (0xA410)

42001

4200142001 (0xA411)

42002

4200242002 (0xA412)

42003

4200342003 (0xA413)

42050

4205042050 (0xA442)

42052

4205242052 (0xA444)

42054

4205442054 (0xA446)

Name Type No. of

registers

Function Byte 1 0 = Off

Product Byte 1 0 = % of Product A

CCF01 Byte 1 0 = linear

CCF05 Byte 1 0 = pure water

Offset Float 2 -100...100 [%] C2.2.2

CCF02 Float 2 - C2.4.2

CCF03 Float 2 - C2.4.3

Values Display

Fct. No.

C2.2.1

2 = Brix 3 = % Mass 4 = Baume 144 5 = Baume 145 6 = % NaOH 7 = Plate 8 = % Volume 9 = API 10 = % Alcohol by mass 11 = % Alcohol by volume

C2.2.3

1 = % of Product B

C2.4.1

1 = non linear

C2.4.5

1 = town water 2 = other

42056

4205642056 (0xA448)

42058

4205842058 (0xA44A)

42060

4206042060 (0xA44C)

42062

4206242062 (0xA44E)

42064

4206442064 (0xA450)

42066

4206642066 (0xA452)

42068

4206842068 (0xA454)

42070

4207042070 (0xA456)

CCF04 Float 2 - C2.4.4

CCF06 Float 2 - C2.4.6

CCF07 Float 2 - C2.4.7

CCF08 Float 2 - C2.4.8

CCF09 Float 2 - C2.4.9

CCF10 Float 2 - C2.4.10

CCF11 Float 2 - C2.4.11

CCF12 Float 2 - C2.4.12

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MFC 400

MODBUS PROTOCOL 5

5.8.16 Concentration 2

INFORMATION!

Only available with option "concentration measurement".

Modbus Function Codes "Read Holding Registers" (0x03) and "Write Multiple Registers" (0x10)

Holding Register

42100

4210042100 (0xA474)

42101

4210142101 (0xA475)

42102

4210242102 (0xA476)

42103

4210342103 (0xA477)

42150

4215042150 (0xA4A6)

42152

4215242152 (0xA4A8)

42154

4215442154 (0xA4AA)

Name Type No. of

registers

Function Byte 1 0 = Off

Product Byte 1 0 = % of Product A

CCF01 Byte 1 0 = linear

CCF05 Byte 1 0 = pure water

Offset Float 2 -100...100 [%] C2.3.2

CCF02 Float 2 - C2.5.2

CCF03 Float 2 - C2.5.3

Values Display

Fct. No.

C2.3.1

2 = Brix 3 = % Mass 4 = Baume 144 5 = Baume 145 6 = % NaOH 7 = Plate 8 = % Volume 9 = API 10 = % Alcohol by mass 11 = % Alcohol by volume

C2.3.3

1 = % of Product B

C2.5.1

1 = non linear

C2.5.5

1 = town water 2 = other

42156

4215642156 (0xA4AC)

42158

4215842158 (0xA4AE)

42160

4216042160 (0xA4B0)

42162

4216242162 (0xA4B2)

42164

4216442164 (0xA4B4)

42166

4216642166 (0xA4B6)

42168

4216842168 (0xA4B8)

42170

4217042170 (0xA4BA)

CCF04 Float 2 - C2.5.4

CCF06 Float 2 - C2.5.6

CCF07 Float 2 - C2.5.7

CCF08 Float 2 - C2.5.8

CCF09 Float 2 - C2.5.9

CCF10 Float 2 - C2.5.10

CCF11 Float 2 - C2.5.11

CCF12 Float 2 - C2.5.12

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6 APPLICATION SEQUENCES

6.1 Saving and restoring the configuration setting

MFC 400

1Start

2 Change Configuration

2a Write Holding Register(s)

2b [changes done]

3a [discard]

3b [apply]

4 Discard Changes

4a Set Coil 1003 (0x03EB)

MB-Telegram: 01 05 03 EB FF 00 + CRC

5 Previous configuration retained

6 Apply Changes

6a Set Coil 1002 (0x03EA)

MB-Telegram: 01 05 03 EA FF 00 + CRC

7 New configuration applied

The example assumes slave address 1 for Modbus telegram.

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MFC 400

6.2 Zero calibration

APPLICATION SEQUENCES 6

1Start 6aFailed - Sensor not measuring 2 Start Zero Calibration 6b Failed - Zero too high 2a Set Coil 2000 (0x07D0)

MB-Telegram: 01 05 07 D0 FF 00 + CRC 3 Check Status Of Zero Calibration 7 Calibration Failure 3a Read Coil 2000 (0x07D0)

MB-Telegram: 01 01 07 D0 00 01 + CRC 4a running 8a Read Input Register 20001 (0x4E21)

4b ready 9 Write new Zero Flow Offset 5

Read Result 5a

Read Input Register 20000 (0x4E20)

MB-Telegram: 01 04 4E 20 00 01 + CRC

• The example assumes slave address 1 for Modbus telegram.

• Substitute "xx xx xx xx" with value read from Input Register 20001.

6c successful

8 Read new Zero Flow Offset

MB-Telegram: 01 04 4E 21 00 02 + CRC

9a Write Holding Register 46000 (0xB3B0)

MB-Telegram:

01 10 B3 B0 00 02 04 xx xx xx xx + CRC 10 Apply Changes 10a Set Coil 1002 (0x03EA)

MB-Telegram: 01 05 03 EA FF 00 + CRC 11 Calibration Done

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7 TROUBLESHOOTING

7.1 No response to Modbus requests

There are a number of possibilities why no response would be received from the signal converter. Here is a list of some of the more obvious things to check:

• Check that there is an appropriate voltage input on the V+ and V- terminals of the signal converter.

• Ensure that there is continuity between the A and B input terminals and their associated terminals at the master device. Check that A and B are connected correctly (details on page

6). Ensure that there is a proper "Common" connection between the master device and the signal converter.

• The signal converter will ignore messages that are not addressed to it, or any message that contains fundamental formatting errors. So, check that the Address ID that is being requested is correct, the default value is 1. Check that the transmission rate (default = 19200 Baud) and format (default = 8 data bits, even parity and 1 stop bit) are correct.

7.2 Communication errors

Intermittent communication errors can have a number of causes, almost all of which can be attributed to the quality of the connection between the master device and the signal converter, such as:

MFC 400

• Low quality connections at the terminals of the signal converter or master device. Ensure that good contact is being made and that the connections are not frayed or corroded.

• Cable lengths and/or cable capacitance are too great for the data rates being used.

• Powerful sources of electromagnetic interference in close proximity to the path of the cable

route.

• It is common to use converter devices to connect the Modbus RS485 output of the signal converter to the serial RS232 port or USB port of a host PC using off-the-shelf protocol converters. Many of these, especially USB based converters will have problems operating the Modbus interface as it is a timing critical protocol. Where possible, a dedicated RS485 interface PC card should be used.

7.3 Responding with exception "Illegal Function"

There can be two reasons why this error response will be returned by the signal converter in answer to a request:

• The function being requested is not valid for the signal converter; check the list of valid Modbus functions. For further information refer to

• An attempt is being made to write to a register that is protected by the Custody Transfer Lock.

Supported Function Codes

on page 11.

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MFC 400

TROUBLESHOOTING 7

7.4 Responding with exception "Illegal Data Address"

There are four reasons why the signal converter will return an "Illegal Data Address" error message when the master device makes a request.

a) The register address being requested is not supported by the signal conveter, check the requested register against the registers specified in the section "Parameters".

b) Although the start address is valid, when accessing multiple registers the number of registers requested may extend beyond the end of the valid address range for that group of variables. Check the number of variables requested and ensure that the last register address is valid.

c) The number of registers requested is not correct for the data type being requested. For example, if registers containing floating point variables are requested then the number of requested registers must be a multiple of 2 as the floating point variables are held in two consecutive registers. For double precision floating point variables the number of registers requested must be a multiple of 4.

d) From c) above, the system will respond with an "Invalid Address" error when an attempt is made to access the associated registers of a multi-register variable, for example when access to the second register of a floating point variable is attempted. i.e. if an attempt is made to access Input register 30001, which contains the second half of the variable accessed by Input register

30000.

7.5 Responding with exception "Illegal Data Value"

When the signal converter responds with an "Illegal Data Value", it is because the value being written to a holding register in the signal converter is beyond the permitted limits for that register. The limits for each holding register are indicated in the section "Parameters".

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8 APPENDIX

8.1 NAMUR NE 107 Event Group(s)

Modbus Input Register

39004 39005

Byte 0 Byte 1 Byte 2 Byte 3

MFC 400

Byte Bit Status

Event group

signal

3 7 - reserved

6 - reserved

5 - reserved

4 - reserved

3 - reserved

2 I Config: No Meas. Value

1 I Electr: Operation Info

0 - -

2 7 F Proc: Current Input 1

6 S Electr: IO Connection 1

5 F Proc: Signal Search 1

4 S Proc: 2 Phase Flow 1

3 S Proc: Signal Low 1

2 S Config: Totaliser 1

1 I Proc: System Control 1

0 I Electr: Power Failure 1

1 7 S Sensor

6 S Electronics

5 S Configuration

4 S Process

3 M Sensor

2 M Electronics

1 M Configuration

0 M Process

0 7 F Sensor

6 F Electronics

5 F Configuration

4 F Process

3 C Sensor

2 C Electronics

1 C Configuration

0 C Process

1 Those event groups can be mapped to any status signals.

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Page 33

MFC 400

8.2 NAMUR NE 107 status signals

APPENDIX 8

FFailure

Failure

FailureFailure Output signal invalid due to malfunction in the signal converter.

C Function Check

Function Check

Function CheckFunction Check Output signal temporarily invalid due to ongoing work on the signal converter.

S Out of specification

Out of specification

Out of specificationOut of specification

• Deviations from the permissible ambient or process conditions determined by the signal converter itself through self-monitoring.

• Faults in the signal converter itself indicate that the measuring uncertainty of flow sensors or deviations from the set value in actuators is probably greater than expected under operating conditions.

M Maintenance required

Maintenance required

Maintenance requiredMaintenance required Although the output signal is valid, the wear reserve is nearly exhausted or a function will soon be restricted due to operational conditions.

8.3 Supported Modbus function codes

Function Code 0x01: Read Coils

Request Response Error

Function 0x01 Function 0x01 Function 0x81

Starting Address Hi0x00 to 0xFF Byte Count n Exception Code 0x01 / 0x02 /

Starting Address Lo0x00 to 0xFF Coil n Status

Quantity of Coils Hin (0x00 to 0x07) ... ...

Quantity of Coils Lon (0x01 to 0xFF)

max Quantity: 0x07D0

0x03 / 0x04

Function Code 0x02: Read Discrete Inputs

Request Response Error

Function 0x02 Function 0x02 Function 0x82

Starting Address Hi0x00 to 0xFF Byte Count n Exception Code 0x01 / 0x02 /

Starting Address Lo0x00 to 0xFF Input n Status

Quantity of Registers Hi

Quantity of Registers Lo

n (0x00 to 0x07) ... ...

n (0x01 to 0xFF)

max Quantity: 0x07D0

0x03 / 0x04

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Function Code 0x03: Read Holding Registers

Request Response Error

Function 0x03 Function 0x03 Function 0x83

Starting Address Hi0x00 to 0xFF Byte Count 2 * n Exception Code 0x01 / 0x02 /

Starting Address Lo0x00 to 0xFF Register n Value

Quantity of Registers Hi

Quantity of Registers Lo

0x00 Register n Value

n (0x01 to 0x7D) ... ...

0x03 / 0x04

Function Code 0x04: Read Input Register

Request Response Error

Function 0x04 Function 0x04 Function 0x84

Starting Address Hi0x00 to 0xFF Byte Count 2 * n Exception Code 0x01 / 0x02 /

Starting Address Lo0x00 to 0xFF Input Register n

Quantity of Input Registers Hi

Quantity of Input Registers Lo

0x00 Input Register n

n (0x01 to 0x7D) ... ...

0x03 / 0x04

Function Code 0x05: Write Single Coil

Request Response Error

Function 0x05 Function 0x05 Function 0x85

Output Address Hi 0x00 to 0xFF Output Address Hi 0x00 to 0xFF Exception Code 0x01 / 0x02 /

Output Address Lo 0x00 to 0xFF Output Address Lo 0x00 to 0xFF

Output Value Hi 0x00 or 0xFF Output Value Hi 0x00 or 0xFF

Output Value Lo 0x00 Output Value Lo 0x00

0x03 / 0x04

Function Code 0x08: Diagnostics

Request Response Error

Function 0x08 Function 0x08 Function 0x88

Sub-function Hi 0x00 to 0xFF Sub-function Hi 0x00 to 0xFF Exception Code 0x01 / 0x03 /

Sub-function Lo 0x00 to 0xFF Sub-function Lo 0x00 to 0xFF

Data n Hi 0x00 to 0xFF Data n Hi 0x00 to 0xFF

Data n Lo 0x00 to 0xFF Data n Lo 0x00 to 0xFF

... ... ... ...

0x04

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APPENDIX 8

Function Code 0x10: Write Multiple Registers

Request Response Error

Function 0x10 Function 0x10 Function 0x90

Starting Address Hi0x00 to 0xFF Starting Address Hi0x00 to 0xFF Exception Code 0x01 / 0x02 /

Starting Address Lo0x00 to 0xFF Starting Address Lo0x00 to 0xFF

0x03 / 0x04

Quantity of Registers Hi

Quantity of Registers Lo

Byte Count 2 * n (0x02 to

... ...

0x00 Quantity of

Registers Hi

0x01 to 0x7B Quantity of

Registers Lo

0xFF)

0x00

0x01 to 0x7B

Function Code 0x2B: Encapsulated Interface Transport 0x0E Read Device Identification

Request Response Error

Function 0x2B Function 0x2B Function 0xAB

MEI Type 0x0E MEI Type 0x0E Exception Code 0x01 / 0x02 /

Read Device ID Code

Object ID 0x00 to 0xFF Conformity Level 0x02 (0x01 /

0x01 / 0x02 (0x03 / 0x04)

Read Device ID Code

More Follows 0x00 (or 0xFF)

Next Object ID 0x00 to 0xFF

Number of Objects

Object n ID 0x00 to 0xFF

Object n length 0x00 to 0xFF

Object n value n (1...254 bytes)

... ...

0x01 / 0x02 (0x03 / 0x04)

0x03 / 0x04)

0x01 to 0x07 (0xFF)

0x03 / 0x04

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8.4 Number format

• Hexadecimal values are written in the format 0xNNNN, where NNNN is the hexadecimal value.

• Decimal values are written in the format 0dNNNN or NNNN, where NNNN is the decimal value.

8.5 Glossary

RTU Remote Terminal Unit mode is a Modbus serial transmission mode RS232 TIA/EIA-232 Standard RS485 TIA/EIA-485 Standard Master/Client A device that polls one or more slave devices and always initiates

Slave/Server A device that responds to requests from a master and never initiates

CRC Cyclic Redundancy Checksum Register A Modbus data object corresponding to a word (16 bits) Coil A Modbus data object corresponding to a single bit LSB Least Significant Byte MSB Most Significant Byte lsb least significant bit msb most significant bit

MFC 400

communication

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NOTES 9

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9 NOTES

MFC 400

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NOTES 9

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KROHNE product overview

• Electromagnetic flowmeters

• Variable area flowmeters

• Ultrasonic flowmeters

• Mass flowmeters

• Vortex flowmeters

• Flow controllers

• Level meters

• Temperature meters

• Pressure meters

• Analysis products

• Products and systems for the oil & gas industry

• Measuring systems for the marine industry

Head Office KROHNE Messtechnik GmbH Ludwig-Krohne-Str. 5 47058 Duisburg (Germany) Tel.:+49 (0)203 301 0 Fax:+49 (0)203 301 10389 info@krohne.de

The current list of all KROHNE contacts and addresses can be found at: www.krohne.com