Daviteq MBRTU-SAL Salinity Sensor Modbus RTU Output Owner’s Manual

: June 16, 2024
: daviteq

Table of Contents

Introduction
Specifications
Wiring
Maintenance and Precautions
- Maintenance
- Note
- Other
Modbus RTU Protocol
Dimensions
Contact
References
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Daviteq MBRTU-SAL Salinity Sensor Modbus RTU Output

Daviteq MBRTU-SAL Salinity Sensor Modbus RTU Output

This document is applied for the following products.

Introduction

MBRTU-SAL is a salinity sensor based on electrodeless inductive measurement. It uses the generator to generate an alternating magnetic field in the primary coil to generate an induced current in the medium. The intensity of the induced current depends on the concentration of ions in the medium. The induced current creates another magnetic field in the secondary coil. The receiver measures the induced current on the coil to determine the salinity of the medium. At the same time, the built-in temperature sensor can automatically compensate the temperature, which is suitable for online long- term monitoring of the environment.

Application scope: Marine, industrial wastewater, pharmaceutical, biotechnology, industrial manufacturing and other online whole process monitoring.

Features

The built-in temperature sensor can automatically compensate the temperature
There is no electrode, so there is no polarization reaction
The measurement and the medium are completely electrically isolated, which can be used for high-precision measurement of heavy and easily precipitated medium or solution with low cost of use and maintenance
Low power consumption and anti-interference design of internal circuit

Specifications

Item	Specifications
Output	Rs-485,MODBUS/RTU
Measuring Method	Non contact electromagnetic principle
Range	0 ~ 70PSU
Accuracy	±1%F.S. or ±0.2PSU(Below 10psu)
Resolution	0.1PSU
Working Environment	0 ~ 65℃; < 0.6MPa
Calibration Method	Two point calibration
Respond Time	10 seconds T90
Temperature Compensation	Automatic temperature compensation(PT1000)
Power Supply	12-24VDC±10%, 10mA;
Size	Diameter 30mm; Length 185.5mm;
Protection level	IP68; The water depth is 20 meters; Other

customization
Service Life| 3 years or above
Cable| 5m
Sensor housing material| PVC;PEEK;

Wiring

Please wiring as shown below:

Wire color	Description
Brown	Power (12-24VDC)
Black	GND
Blue	RS485A
White	RS485B
Bare line	Shielding Layer

Wiring

Maintenance and Precautions

Maintenance

Inductive electrode is basically maintenance free; It is recommended to clean up the sensor probe attachment every 30 days; Avoid the use of hard objects to cause the damage of the light guide part of the measuring probe during cleaning; Please wipe with a soft damp cloth.
It is recommended to clean the outer surface of the sensor with water flow. If there is still debris residue, please wipe it with a wet soft cloth.

Note

Installation measurement: avoid the installation measurement at the place where the water flow is turbulent, and reduce the influence of water bubbles on the measurement. Keep the measuring probe 2cm away from the bottom.
The probe of the sensor is fouling or attached with more organisms, so the cleaning force can be increased appropriately. Slight scratch on the probe surface does not affect the normal use of the sensor. But pay attention not to penetrate the shell of the probe.
Suggestion: the protective cover of our company should be selected to prevent the influence of microbial attachment on the measurement results.

Other

Problem	Possible Causes	Solution

The operation interface cannot be connected or the measurement results are not displayed are not displayed| Wrong cable connection| Check the wiring mode
Wrong sensor address| Check the address for errors
The measured value is too high, too low or the value is continuously unstable.| The sensor probe is attached by
foreign objects| Clean the sensor probe surface
Other| Contact after sales

Modbus RTU Protocol

Information frame form

The default data format for Modbus communication of this sensor is:

MODBUS-RTU

Function code 03: read (R) register value
Function code 06: write (W) single register value

Register Address

Register Address (hex)

| Name| R/W| Introductions| Number of registers (byte)| Data type
---|---|---|---|---|---
0x0100| Temperature value| R| ℃ value x10 (for example: the temperature of 25.6℃ is displayed as 256, the default is 1 decimal.)| 1 (2 bytes)| unsigned short

Data structure type

Integer

unsigned int (unsigned short).

The data consists of two integers.

XXXX XXXX	XXXX XXXX
Byte1	Byte0

Float

Float, According to IEEE 754 (single precision);

The data consists of 1 sign bit, 8-bit exponent, and a 23 bit mantissa.

XXXX XXXX	XXXX XXXX	XXXX XXXX	XXXX XXXX
Byte3	Byte2	Byte1	Byte0
Sign bit	Exp digit	F decimal

Modbus RTU command

Function code 03h: read register value

Host send

1	2	3	4	5	6	7	8
ADR	03H	Start register high byte	Start register low byte	Register number
high byte	Number of registers low byte	CRC low byte	CRC high byte

The first byte ADR: slave address code (= 001 ~ 254)
Byte 2 03h: read register value function code
Byte 3 and 4: start address of register to be read
To read the FCC instrument,
Bytes 5 and 6: number of registers to read
Bytes 7 and 8: CRC16 checksums from bytes 1 to 6

Slave return

1	2	3	4 , 5	6 , 7		M-1 , M	M+1	M+2
ADR	03H	total bytes	Register data 1	Register data 2	……	Register data M
CRC low byte	CRC high byte

The first byte ADR: slave address code (= 001 ~ 254)
Byte 2 03h: return to read function code
The third byte: the total number of bytes from 4 to m (including 4 and m)
Bytes 4 to m: register data
Byte m + 1, M + 2: CRC16 check sum from byte 1 to M

When the slave receives an error, the slave returns the error:

1	2	3	4	5
ADR	83H	Information code	CRC low byte	CRC high byte

The first byte ADR: slave address code (= 001 ~ 254)
Byte 2 83h: error reading register value
Byte 3 information code: 01 – function code error
03 – data error
Bytes 4 and 5: CRC16 checksums from bytes 1 to 3

Function code 06h: write single register value

Host send

1	2	3	4	5	6	7	8
ADR	06	Register high byte address	Register low byte address	Data high
byte	Data low byte	CRC code Low byte	CRC code High byte

When the slave receives correctly, the slave sends back:

1	2	3	4	5	6	7	8
ADR	06	Register high byte address	Register low byte address	Data high
byte	Data low byte	CRC code Low byte	CRC code High byte

When the slave receives an error, the slave returns:

1	2	3	4	5
ADR	86H	Error code information code	CRC code Low byte	CRC code High byte

The first byte ADR: slave address code (= 001 ~ 254)
The second byte 86h: write register value error function code
Byte 3 error code information code: 01 – function code error
03 – data error
Byte 4 and 5: CRC checksum from byte 1 to 3

Command example

Default register:

a) Change slave address:

Address: 0x2000 (42001)
Number of registers: 1
Function code: 0x06
Default sensor address: 01

Change the Modbus device address of the sensor, and change the device address from 01 to 06. The example is as follows:

Send command: 01 06 20 00 00 06 02 08
Respond: 01 06 20 00 00 06 02 08; Note: the address is changed to 06 and stored after power failure.

b) Baud rate:

Address: 0x2003 (42004)
Number of registers: 1
Function code: 0x06
Default value: 1 (9600bps)
Supported values: 0-2 (4800-19200bps)

The baud rate can be changed by the upper computer setting, and it can work without restart after the change. The baud rate saves the upper computer setting after power failure. Baud rate support 4800 9600 19200. The baud rate of integer value allocation is as follows:

Integer	Baud rate
0	4800 bps
1	9600 bps
2	19200 bps

Send command: 01 06 20 03 00 02 F3 CB
Respond: 01 06 20 03 00 02 F3 CB Note: the baud rate is changed to 19200bps and saved after power failure

Function register:

a) Measuring temperature command:

Address: 0x0100 (40101)
Number of registers: 1
Function code: 0x03
Read sample values: 19.2℃

Send command: 01 03 01 00 00 01 85 F6
Respond: 01 03 02 00 C0 B8 14
Returns hexadecimal unsigned integer data, temperature value = integer / 10, 1 bit decimal place is reserved.

b) Salinity measurement instruction:

Address: 0x0101 (0x40102)
Number of registers: 1
Function code: 0x03
Read sample values: 9.1PSU

Send command: 01 03 01 01 00 01 D4 36
Respond: 01 03 02 00 5B F9 BF
Register returns hexadecimal unsigned integer data, salinity value = integer / 10, 1 decimal place reserved.

c) Continuous reading of temperature and salinity instructions:

Address: 0x0100 (40101)
Number of registers: 2
Function code: 0x03
Read sample values: Temperature 19.2 ℃ and salinity 9.1 PSU

Send command: 01 03 01 00 00 02 C5 F7
Respond: 01 03 04 00 C0 00 5B BB F4
Register returns hexadecimal unsigned integer data, temperature value = integer / 10, 1 decimal place reserved
Register returns hexadecimal unsigned integer data, salinity value = integer / 10, 1 decimal place reserved.

d) Humidity measurement command:

Address : 0x0107 (40108)
Number of registers: 1
Function code: 0x03
Read sample values: relative humidity 40%

Send command: 01 03 01 07 00 01 34 37
Respond: 01 03 02 01 90 B9 B8
Register returns hexadecimal unsigned integer data, humidity value = integer / 10, 1 decimal place reserved.

Calibration instruction:

a) Temperature calibration

Address: 0x1000 (41001)
Number of registers: 1
Function code: 0x06

Calibration example: calibration at 25.8 ° C
Send command: 01 06 10 00 01 02 0D 5B
Respond: 01 06 10 00 01 02 0D 5B
The sensor needs to be calibrated in a constant temperature environment after the temperature indication no longer fluctuates.

b) Salinity zero calibration

Address: 0x1001 (41002)
Number of registers: 1
Function code: 0x06

Calibration example: calibration in air
Send command: 01 06 10 01 00 00 DC CA
Respond: 01 06 10 01 00 00 DC CA

c) Salinity slope calibration

Address: 0x1003 (41004)
Number of registers: 1
Function code: 0x06

Calibration example: calibration in 50 PSU salinity solution
Send command: 01 06 10 03 01 F4 7D 1D
Respond: 01 06 10 03 01 F4 7D 1D

Dimensions

Contact

Manufacturer
Lofo No.11 Street 2G, Nam Hung Vuong Res., An Lac Ward, Binh Tan Dist., Ho Chi Minh City, Vietnam.
Tel: +84-28-6268.2523/4 (ext.122)
Email: info@daviteq.com | www.daviteq.com