Truflo MF-1000 In-Line Magnetic Flow Meter - MODBUS Protocol

Read the user's manual carefully before starting to use the unit. The producer reserves the right to implement changes without prior notice.

MODBUS Protocol

The MF1000 Magnetic Flow Meter supports the Modbus-RTU protocol, which can be customized according to user needs. When selecting bus control, choose the required protocol in the communication settings. In this document, the term "slave" refers to the Magnetic Flow Meter.

Types and Formats of Communication Data

Information is transmitted asynchronously in bytes. The communication information between the master station and the slave station uses a 10-bit word format:

Start bit: 1 bit
Data bit: 8 bits
Parity bit: None
Stop bit: 1 bit

Communication Data (Information Frame) Format

Data Format	Address Code	Function Code	Data Area	CRC Check
Data Length	1 bit	1 bit	N bit	16-bit CRC code (redundant cyclic code)

Communication Information Transmission Process

When a communication command is sent from the master device to the flow meter, the flow meter matching the address code receives the command. It reads the information based on the function code and related requirements. If the CRC check is correct, the command is executed, and the result (data) is returned to the host. The returned information includes the address code, function code, executed data, and CRC check code. If there is a CRC error, no information is returned.

1.1 Address Code

The address code is the first byte (8 bits) of each communication information frame, ranging from 0 to 255. This byte indicates the slave address that should receive the information sent by the master. Each slave must have a unique address code. When the slave sends back information, the returned data starts with its own address code. The address code sent by the master indicates the target slave address, and the address code returned by the slave indicates the source of the information.

1.2 Function Code

This is the second byte transmitted in each communication information frame. Modbus communication protocol defines function codes from 1 to 127. The smart electromagnetic flowmeter uses a subset of these function codes. The master sends a function code to instruct the slave on the action to perform. The slave returns the same function code in its response, indicating that it has responded and performed the related operations.

MODBUS Part Function Codes
Function Code	Definition	Operation (binary)
03	Read Register Data	Read data from one or more registers
10	Write multiple registers	Write multiple sets of binary data to multiple registers

1.3 Data Area

The data area contains the information to be returned or the action to be performed by the slave. This can include data like instantaneous flow, flow rate, cumulative flow, or reference addresses. For example, using function code 03, the master can request register values, specifying the start address and length. The returned data includes the data length and content. Data addresses and information vary between different slaves.

The intelligent electromagnetic flowmeter uses the Modbus communication protocol. The host (PLC, RTU, PC, DCS, etc.) can read its data registers using communication commands. Variables stored in the data registers are 16-bit (2 bytes) binary data, with the high byte first. Up to 50 registers can be read at once. A single variable might consist of 4 bytes of data, requiring two reads for the high and low bytes (e.g., positive cumulative flow).

The slave response format includes the slave address, function code, data area, and CRC code. Data in the data area is two bytes, with the high byte preceding the low byte.

1.4 Standstill Time Requirements

Before sending data, a data bus static time is required. This means the time without data transmission should not exceed 50ms at a baud rate of 9600.

1.5 Timeout Requirements

After the host sends a command, the timeout time should be greater than 200ms at a baud rate of 9600.

2. Introduction to MODBUS Function Codes

2.1 Function Code "03": Read Multiple Register Input

Example: The master wants to read data from 3 slave registers (slave address 01, starting address 000E).

Slave Data Register Address and Data
Register Address	Register Data (Hexadecimal)	Corresponding Variable
000E	0180	Variable 1
000F	0180	Variable 2
0010	0180	Variable 3

Message Format Sent by Host (Read Registers)
Sent by Host	Number of Bytes	Information Sent	Remarks
Slave Address	1	01	Send to slave with address 01
Function Code	1	03	Read register
Start Address	2	000E	The start address is 0x000E
Data Length	2	0003	Read 3 registers (6 bytes in total)
CRC Code	2	6408	The CRC code is calculated by the host

Message Format Returned by Slave Response (Read Registers)
Slave Response	Bit No.	Message Return	Remarks
Slave Address	1	01	From slave 01
Function Code	1	03	Read register
Returns the number of bytes	2	06	3 registers total 6 bytes
Register Data 1	2	0180	Contents of memory at address 0x000E
Register Data 2	2	0180	Contents of memory at address 0x000F
Register Data 3	2	0180	Contents of memory at address 0x0010
CRC Code	2	215E	The CRC code is calculated by the meter

2.2 Function Code "10": Write Multiple Registers

The master uses this function code to save multiple data to the slave meter's data memory. A register is 16 bits (2 bytes), with the high bit first. The slave memory is two bytes. The Modbus protocol allows saving up to 60 registers at a time.

Example: The host wants to save 0003 and 00FF to slave registers 003A and 003B (slave address 01).

Message Format Sent by Host (Write Registers)
Sent by Host	Number of Bytes	Sending Information	Example
Slave Address	1	01	Send to slave 01
Function Code	1	10	Write multiple registers
Start Address	2	003A	The start address of the register to be written
Number of Storage Registers	2	0002	Number of storage registers (2 in total)
Save data byte length	1	04	Save data byte length (total 4 bytes)
Save data 1	2	0003	Data address 003A
Save data 2	2	00FF	Data address 003B
CRC Code	2	C084	CRC code calculated by the host

Message Format Returned by Slave Response (Write Registers)
Slave Response	Number of Bytes	Message Return	Example
Slave Address	1	01	From slave 01
Function Code	1	10	Write multiple registers
Start Address	2	003A	The start address is 003A
Save the Number of Registers	2	0002	Save the data of 2 registers
CRC Code	2	61C5	CRC code calculated by the slave

2.3 Error Check Code (CRC Check)

The CRC check code allows the host or slave to verify the correctness of received information. It helps detect errors caused by electronic noise or interference during transmission. The CRC in the Modbus protocol is a 2-byte (16-bit) binary number. The sending device calculates and appends it to the information frame. The receiving device recalculates the CRC and compares it with the received CRC. A mismatch indicates an error. The CRC calculation uses only the 8 data bits, excluding start, stop, and parity bits.

3. Communication Error Information and Data Processing

When the flowmeter detects an error other than a CRC error, it returns an error code to the master. The highest bit of the function code is set to 1 (function code + 128) to indicate an unexpected error. If the slave receives information with a CRC error, it ignores the message.

The format of the error code returned by the slave (excluding CRC) is:

Address Code: 1 byte
Function Code: 1 byte (highest bit is 1)
Error Code: 1 byte
CRC Code: 2 bytes

The slave responds with the following error codes:

81: Illegal function code. The received function code is not supported by the slave.
82: Read illegal data address. The specified data location is outside the readable address range of the slave.
83: Illegal data value. The received data value sent by the master exceeds the data range of the corresponding address of the slave.

4. Data Format Description

RO: Read-only parameter; RW: Readable and writable parameters; DW: 4-byte data (high 2 bytes and low 2 bytes transmitted separately); W: 2 bytes of data; B: Single-byte data (zero-filled to 2 bytes in Modbus, high byte is 0); SF: 4-byte data, floating-point format (transmitted as two 2-byte registers).

Data is presented in three formats: unsigned integer, signed integer, and floating-point.

Unsigned integer data: Many values are unsigned integers. DW*1000 indicates data is magnified by 1000 (e.g., 0.001 is represented as 1).
Signed integer data: Zero point correction data can be positive or negative. The highest bit indicates the sign (0 for positive, 1 for negative).
Floating-point format: Uses IEEE754 32-bit format (4 bytes, two registers). Structure: S EEEEEEE E MMMMMMMM MMMMMMMM MMMMMMMM, where S is the sign bit, E is the exponent (difference from 127), and M is the mantissa (lower 23 bits). Conversion formula: V=(-1)^S * 2^(E-127) * (1+M) when E is not all 0s or all 1s.

4.1 Special Function Description

The protocol supports clearing cumulative amounts for batch control. Accumulator clearing corresponds to registers 96 and 97. To clear, write the accumulated amount clearing password to these registers. Contact the manufacturer for the reset password.

Alarm_Bits Description: Bit 1: Upper limit alarm, Bit 2: Lower limit alarm, Bit 3: Empty pipe alarm, Bit 4: Excitation alarm.

Flow Unit Definitions
Flow_Unit	Unit
0	L/H
1	L/M
2	L/S
3	M³/H
4	M³/M
5	M³/S
6	KG/H
7	KG/M
8	KG/S
9	T/H
10	T/M
11	T/S

Throughput Unit Definitions
Throughput_Unit	Unit
0	0.001 L
1	0.01 L
2	0.1 L
3	1 L
4	0.001 M³
5	0.01 M³
6	0.1 M³
7	1 M³
8	1 KG
9	1 T

Excitation Frequency Definitions
Excitation_Freq	Frequency
0	1/32 Power Frequency
1	1/16 Power Frequency
2	1/8 Power Frequency
3	1/4 Power Frequency
4	1/2 Power Frequency

Excitation Current Definitions
Excitation_Current	Current
0	100 %
1	90 %
2	80 %
3	70 %
4	55 %
5	40 %
6	20 %
7	0 %

Measure Direction Definitions
Measure_Direction	Direction
0	Reverse
1	Forward

Output Pulse Definitions
Output_Pulse	Type
0	Frequency Output
1	Pulse Output

Pulse Unit Definitions
Pulse_Unit	Unit
0	0.001 L
1	0.01 L
2	0.1 L
3	1 L
4	0.001 M³
5	0.01 M³
6	0.1 M³
7	1 M³

5. Flow Meter Register Address Definition

5.1 Definition of Common Register Address of Flow Meter

(SF: Single precision floating point format, DW: Double word format, W: Word format)

Register	PLC Memory Address	Unit	Number of Bytes	Attribute	Format	Register Definition
90	40091		4	RO	SF	Forward Cumulative Flow - Float Format
92	40093		4	RO	SF	Reverse Cumulative Flow - Float Format
94	40095		4	RO	SF	Total Cumulative Flow - Float Format
96	40097		4	RW	DW	Cumulative flow reset
98	40099	Refer to Register 105	4	RO	SF	Flow - float format
100	40101	m/s	4	RO	SF	Velocity - float format
102	40103	%	4	RO	SF	Flow Percent - Float Format
104	40105	%	2	RO	W	Empty Tube Percentage
105	40106		2	RO	W	Flow unit
106	40107		2	RO	W	Empty pipe alarm
107	40108		2	RO	W	Excitation alarm

5.2 Definition of All Register Addresses of the Flow Meter

(SF: Single precision floating point format, DW: Double word format, W: Word format)

Variable Address	PLC Memory Address	Unit	Number of Bytes	Attribute	Format	Register Definition
0	40001	m/s	2	R0	DW*1000	Flow Rate - High Byte
1	40002	m/s	2	R0	DW*1000	Flow Rate - Low Byte
2	40003		2	R0	DW*100	Instantaneous traffic - high byte
3	40004		2	R0	DW*100	Instantaneous Traffic - Low Byte
4	40005	%	2	R0	B*100	Flow percentage
5	40006	%	2	R0	B*100	Empty Tube Percentage
6	40007		2	R0	DW*1	Forward Cumulative Flow-High Byte
7	40008		2	RO	DW*1	Forward Cumulative Flow-Low Byte
8	40009		2	RO	DW*1	Reverse Cumulative Flow-High Byte
9	40010		2	RO	DW*1	Reverse Cumulative Flow-Low Byte
10	40011		2	RO	DW*1	reserved address
11	40012		2	RO	DW*1	reserved address
12	40013		2	RO	B*1	Alarm information
13	40014		2	RO	B*1	fluid flow
14	40015		2	RO	DW	System Time - Year - High Byte
15	40016		2	RO	DW	System Time - Year - Low Byte
16	40017		2	RO	B	System Time-Month
17	40018		2	RO	B	System Time-Day
18	40019		2	RO	B	System time-hour
19	40020		2	RO	B	System time-minute
20	40021		2	RO	B	System time-seconds
21	40022	mm	2	RW	W	pipe diameter
22	40023		2	RW	DW	Instantaneous flow range high byte
23	40024		2	RW	DW	Instantaneous flow range low byte
24	40025		2	RW	B	Instantaneous flow unit
25	40026		2	RW	B	cumulative flow unit
26	40027	S	2	RW	W*1	Response time
27	40028		2	RW	W*10000	Sensor parameters
28	40029	HZ	2	RW	B	Excitation frequency
29	40030	%	2	RW	B	Excitation current
30	40031		2	RW	B	Measuring direction setting
31	40032	mm/s	2	RW	W	Zero Point Correction
32	40033	%	2	RW	W*100	small signal point cut-off
33	40034		2	RW	B	Allows for small signal cut-off
34	40035		2	RW	B	Reverse output allows
35	40036		2	RW	B	Empty Pipe Alarm Allowed
36	40037	%	2	RW	B	Empty Pipe Alarm Threshold
37	40038		2	RW	B	Upper limit alarm allowed
38	40039	%	2	RW	W*100	Upper limit alarm threshold
39	40040		2	RW	B*1	Lower limit alarm allowed
40	40041	%	2	RW	W*100	Lower limit alarm threshold
41	40042		2	RW	B	High temperature alarm allows
42	40043	C	2	RW	W*100	High temperature alarm threshold
43	40044		2	RW	B	Excitation alarm allows
44	40045		2	RW	B	Pulse frequency output
45	40046		2	RW	B	Pulse equivalent
46	40047	HZ	2	RW	W	Frequency output range
47	40048		2	RW	W	reserved address
48	40049		2	RW	B	reserved address
49	40050		2	RW	B	reserved address
50	40051		2	RW	W	reserved address
51	40052		2	RW	B	reserved address
52	40053		2	RW	B	reserved address
53	40054		2	RW	W	reserved address
54	40055		2	RW	B	reserved address
55	40056		2	RW	B	reserved address
56	40057		2	RW	W	reserved address
57	40058		2	RW	B	reserved address
58	40059		2	RW	B	reserved address
59	40060		2	RW	DW*1000 0	Meter Coefficient - High Byte
60	40061		2	RW	DW*1000 0	Meter Coefficient - Low Byte
61	40062		2	RW	W	Empty Pipe Coefficient A
62	40063		2	RW	W	Empty Pipe Coefficient B
63	40064		2	RW	W	Empty Pipe Coefficient C
64	40065		2	RW	W	Empty Pipe Coefficient D
65	40066		2	RW	W*10000	Converter Normalization Factor
66	40067		2	RW	B	First state filtering allows
67	40068		2	RW	W*10000	First state filter factor
68	40069	Min	2	RO	DW*60	Cumulative Working Hours - High Byte
69	40070	Min	2	RO	DW*60	Cumulative Operating Hours - Low Byte
70	40071		2	RW	DW	Flow Correction Point 1 -High Byte
71	40072		2	RW	DW	Flow Correction Point 1-Low Byte
72	40073		2	RW	DW	Flow Correction Point 2-High Byte
73	40074		2	RW	DW	Flow Correction Point 2-Low Byte
74	40075		2	RW	DW	Flow Correction Point 3-High Byte
75	40076		2	RW	DW	Flow Correction Point 3-Low Byte
76	40077		2	RW	DW	Flow Correction Point 4-High Byte
77	40078		2	RW	DW	Flow Correction Point 4-Low Byte
78	40079		2	RW	DW	Flow Correction Point 5-High Byte
79	40080		2	RW	DW	Flow Correction Point 5-Low Byte
80	40081		2	RW	DW	Flow Correction Factor 1-High Byte
81	40082		2	RW	DW	Flow correction factor 1-low byte
82	40083		2	RW	DW	Flow Correction Factor 2-High Byte
83	40084		2	RW	DW	Flow correction factor 2-low byte
84	40085		2	RW	DW	Flow Correction Factor 3-High Byte
85	40086		2	RW	DW	Flow correction factor3-low byte
86	40087		2	RW	DW	Flow Correction Factor 4-High Byte
87	40088		2	RW	DW	Flow correction factor 4-low byte
88	40089		2	RW	DW	Flow Correction Factor 5-High Byte
89	40090		2	RW	DW	Flow correction factor 5-low byte
90	40091		2	RO	SF	Forward cumulative flow floating point format-high byte
91	40092		2	RO	SF	Forward cumulative flow floating point format-low byte
92	40093		2	RO	SF	Reverse Cumulative Flow Float Format-High Byte
93	40094		2	RO	SF	Reverse Cumulative Flow Float Format-Low Byte
94	40095		2	RO	SF	Total cumulative flow floating point format-high byte
95	40096		2	RO	SF	Total cumulative flow floating point format-low byte
96	40097		2	RW	DW	Cumulative flow reset - high byte
97	40098		2	RW	DW	Cumulated flow reset-low byte
98	40099	refer to Register 105	2	RO	SF	Flow - high byte
99	40100		2	RO	SF	Flow - low byte
100	40101	m/s	2	RO	SF	Flow Rate - High Byte
101	40102	m/s	2	RO	SF	Flow Rate - Low Byte
102	40103	%	2	RO	SF	Flow Percentage-High Bytes
103	40104	%	2	RO	SF	Flow Percentage-Low Bytes
104	40105	%	2	RO	W	Empty Tube Percentage
105	40106		2	RO	W	flow unit
106	40107		2	RO	W	Empty pipe alarm
107	40108		2	RO	W	Excitation alarm
108	40109		2	RO	W	reserved address
109	40110		2	RO	W	reserved address
110	40111		2	RO	W	reserved address
111	40112		2	RO	W	reserved address
112	40113		2	RO	W	reserved address
113	40114		2	RO	W	protocol version
114	40115		2	RO	W	Unit of flow range
115	40116		2	RO	W	Reverse measurement allowed

6. RS485 Flow Reset

Normal Type:

01 10 00 60 00 02 04 00 00 38 50 E6 7B

Byte	Description
01	Table Address
10	Function Code
0060	Register Address
0002	Data Length
04	Digit
00003850	Password
E6 7B	CRC Test

Special Type:

01 10 00 60 00 02 04 00 01 86 9F 86 4F

Byte	Description
01	Table Address
10	Function Code
0060	Register Address
0002	Data Length
04	Digit
0001869F	Password
864F	CRC Test

Warranty, Returns and Limitations

Warranty

Icon Process Controls Ltd warrants its products to the original purchaser to be free from defects in material and workmanship under normal use for one year from the date of sale. Icon Process Controls Ltd's obligation is limited to the repair or replacement of defective products or components at its option. Claims must be made within thirty (30) days of the claimed defect. Repaired products are warranted for the remainder of the original warranty period, and replacement products are warranted for one year from the date of replacement.

Returns

Products cannot be returned without prior authorization from Icon Process Controls Ltd. To return a product, submit a customer return (MRA) request form via www.iconprocon.com. All returns must be shipped prepaid and insured. Icon Process Controls Ltd is not responsible for products lost or damaged in shipment.

Limitations

This warranty does not cover products that are:

Beyond the warranty period or not returned following proper procedures.
Damaged due to improper use, accidents, or negligence.
Modified or altered.
Repaired by unauthorized personnel.
Involved in accidents or natural disasters.
Damaged during return shipment.

Icon Process Controls Ltd reserves the right to waive this warranty and dispose of returned products if hazardous materials are present or if products remain unclaimed for more than 30 days after notification. This warranty is the sole express warranty provided by Icon Process Controls Ltd. All implied warranties, including merchantability and fitness for a particular purpose, are expressly disclaimed. Remedies are limited to repair or replacement. Icon Process Controls Ltd shall not be liable for incidental or consequential damages. This warranty is governed by the laws of the province of Ontario, Canada. If any provision is found invalid, the rest of the warranty remains in effect.

For additional product documentation and technical support, visit www.iconprocon.com, email sales@iconprocon.com or support@iconprocon.com, or call 905.469.9283.

	Truflo TIP Series Flow Meter: Quick Start Guide Quick start guide for the Truflo TIP Series Multi-Function Paddle Wheel Flow Meter by ICON Process Controls. Learn about installation, programming, specifications, and safety.
	Truflo TIP TI3P Series Insertion Paddle Wheel Flow Meter Sensor Quick Start Manual This document provides a quick start guide for the Truflo TIP TI3P Series Insertion Paddle Wheel Flow Meter Sensor. It covers safety information, product description, features, technical specifications, wiring diagrams, installation, fittings, programming, and warranty.
	Truflo TKP/TK3P Series V2 Paddle Wheel Flow Meter Sensor Quick Start Guide Quick start guide for the Truflo TKP and TK3P Series V2 in-line paddle wheel flow meter sensors, detailing installation, safety, specifications, programming, and warranty information.
	Truflo TKB TK3B Series In-Line Paddle Wheel Flow Meter Sensor Quick Start Manual Quick start guide for the Truflo TKB and TK3B Series in-line paddle wheel flow meter sensors. Features include ShearPro design, Tefzel paddle, zirconium bushings, and detailed technical specifications, programming, installation, and warranty information.
	Truflo TIR Series Insertion Paddle Wheel Flow Meter Sensor Quick Start Manual This document provides a quick start guide for the Truflo TIR Series Insertion Paddle Wheel Flow Meter Sensor, covering installation, safety information, and technical specifications.
	Truflo UltraFlo 1000 Series Ultrasonic Flow Meter Datasheet Datasheet for the Truflo UltraFlo 1000 Series Ultrasonic Flow Meter, detailing its features, technical specifications, working principle, and application examples. This meter is designed for high purity and corrosive liquid applications.
	Truflo TIW Series Insertion Paddle Wheel Flow Meter Sensor Quick Start Manual Quick start manual for the Truflo TIW Series Insertion Paddle Wheel Flow Meter Sensor, detailing safety information, product features, specifications, installation, and maintenance.
	Truflo TKB/TK3B Series In-Line Paddle Wheel Flow Meter Sensor Quick Start Manual Quick start guide for the Truflo TKB and TK3B Series in-line paddle wheel flow meter sensors, covering safety, product description, features, technical specifications, model selection, programming, battery replacement, installation, and warranty information.