Daruifuno DEC79 Quick manual

Daruifuno
Conductivity Sensor
Basic User Manual
Model: DEC79
Version 1.0

Contents
Chapter 1 Specification........................................................................................1
Chapter 2 Basic Information.................................................................................2
2.1 Security Information.....................................................................2
2.2 Overview.......................................................................................2
2.3 Dimension.......................................................................................2
Chapter 3 Installation......................................................................................3
3.1 Sensor Installation..........................................................................3
3.2 Sensor Wiring....................................................................................4
Chapter 4 Use................................................................................................5
4.1 Communication..................................................................................5
4.2 Read Measurements.........................................................................5
4.3 Sensor Calibration........................................................................5
4.3.1 Two Points Calibration........................................................................5
4.3.2 Multi-point Calibration.................................................................6
4.3.3 Temperature Correction...................................................................6
4.4.4 Reset Calibration........................................................................6
Chapter 5 Maintenance.........................................................................................7
5.1 Maintenance Cycle...........................................................................7
5.2 Cleaning............................................................................................7
Appendix A Modbus Register Information

Guarantee
Our company seriously warrants each of the instrument for one year (12 months) from
the specific date of delivery. Consumables and consumable parts in the equipment are
not covered by the warranty. The terms of this warranty shall not apply if damage to the
instrument occurs beyond the warranty period, or in the opinion of the company, the
breakage or destruction of the instrument is due to improper use, lack of maintenance,
improper installation, improper modification, abnormal environmental conditions, etc.
The company's obligation under this warranty is limited to providing replacement or
repair of this product, as the case may be. The product must be thoroughly cleaned to
remove any contaminated chemicals before it is accepted for replacement or repair.
Our obligations shall not exceed the price of the product itself. In no event shall the
company be liable for damage caused by incidental or consequential damages,
whether to persons or objects. The company shall not be liable for any other loss,
damage or expense of any kind, including economic loss resulting from the installation,
use or improper use of the product.
For details, please refer to the product's quality promise with the product, and keep
this manual and the quality promise properly.

- 1 -
Measuring Principle
Graphite two electrode measurement principle
Measuring Range
0~20uS/cm, 20~200uS/cm, 200~2000uS/cm, 2~10mS/cm
0.0~50.0℃
Resolution
0.01uS/cm 、0. 1uS/cm 、1uS/cm
0 1℃
Accuracy
±1.0%FS
Temp Compensation
0~50°C, NTC automatic or manual
Calibration Method
Deviation correction,
factor correction,
multi-point calibration
Working Temperature
0~50°C
Working Pressure
≤6bar
Protection Grade
IP68
Power Supply
9~36VDC
Power Consumption
About 0.2W
Electrical isolation
Power and communication are isolated inside the sensor
Communication
Interface
RS485 MODBUS
Shell Material
ABS
Dimension
φ35mm, total length 260mm (include cleaning cover)
Installation Size
One inch 1" NPT thread at both ends
Insertion depth 100mm (including cleaning connector 115mm)
Weight
About 150 (not include the cable)
Cable
PUR (polyurethane) sheath, standard 5 meters,
length can be customized
Connection Method
Default bare wire, M12 plug or waterproof aviation plug to be
customized
Specification
Chapter 1 Specification
Product specifications are subject to change without notice.

- 2 -
Basic Information
Chapter 2 Basic Information
2.1 Security Information
Please read this manual completely before unpacking, installing and operating this
equipment. Pay special attention to all precautions. Otherwise, it may cause serious
personal injury to the operator or damage the equipment.
2.2 Overview
The sensor is based on the principle of two-electrode measurement. Two polar plates parallel
to each other are put into the measured solution, and a driving voltage is applied to both ends
of the polar plates. The conductivity of the solution is measured according to the current
intensity between the polar plates.
The sensor electrode plate is made of graphite material, which can minimize the polarization
effect and ensure the measurement accuracy. The sensor measurement unit is designed for
replacement structure, which reduces the replacement and maintenance costs of users during
use.
The sensor is suitable for sewage plants, water plants, water stations, surface water,
environmental protection water treatment, metallurgical electronics, mining, paper industry,
semiconductors and other fields. It can continuously monitor the conductivity of aqueous
solutions.
2.3 Dimensions
Figure 1 Dimensions of the sensor

- 3 -
1-DN60U card
7-M48 Nut*4
2-plate
8-Eight-character clip 25&32
3-Handle sleeve
9-M4*25 screw*2
4-DN40U card
10-handle
5-M6 Nut*8
11-DN32PVC Bracket
6-Rainproof elbow
12-1 inch inner wire straight pipe joint
Installation
Chapter 3 Installation
3.1 Sensor Installation
Refer to the pictures in this section to install and fix the sensor. To ensure that the sensor can
measure safely and accurately, the following conditions must be met during installation:
In pipeline installation, the sensor should be installed at a low position in the pipeline, with a
stable flow rate and not prone to air bubbles;
In the case of submerged installation, the front section of the sensor should be installed
facing the direction of the water flow, and should go deep into the active water body;
The measuring part of the sensor must be kept clean during installation. Do not touch the
inner surface of the electrode with your hands or dirty objects. After touching oily or
glue-like objects, it will not be able to accurately measure for a long time;
It is forbidden for the sensor wire to be threaded and bound together with the power line to
avoid interference with the measurement or breakdown of the sensor measurement unit
when it is damaged.
Figure 2 Schematic diagram of railing installation

- 4 -
1-Flow cell
4-pH sensor fixed connection cover
2-Flow cell cover
5-DO sensor fixed connection cover
3-Turbidity sensor fixed connection cover
6-Conductivity sensor fixed connection cover
Wire Color
Red
Black
White
Green
Terminal Definition
+12V
DC
Power
ground
RS485 data A
(+)
RS485 data B
(-)
Instrument Terminal Symbols
V+
V-
AS
BS
Sensor Wiring
Overflow
water intake
Outlet
Figure 3 Schematic diagram of installation of five-parameter flow cell
3.2 Sensor Wiring
The sensor is correctly connected as defined in the table below.

- 5 -
Use
Chapter 4 Use
4.1 Communication
The sensor communication is RS485 Modbus-RTU, please refer to Modbus related protocol
description for specific communication protocol.
The default communication parameters of the sensor are: communication address=17, baud
rate=9600, parity bit=none, stop bit=1 bit, the information parameters can be modified by
referring to the register description in Appendix A
4.2 Read Measurements
Sensor measurements can be read by connecting the meter or using other Modbus master
devices.
Please refer to Appendix A for the Modbus register address of the device.
The sensor measurement data is 4-byte floating point data, and the data sequence is little
endian-byte exchange, pay attention to the conversion order.
4.3 Sensor Calibration
The sensor provides two measurement calibration methods, two-point calibration and
multi-point calibration. Normally, two-point calibration can meet daily calibration and
maintenance. When the sensor measurement deviation is large or the measurement unit is
replaced, multi-point calibration is required.
4.3.1 Two Points Calibration
The two-point calibration corrects the sensor measurement value through the "deviation
value" and "factor value". The relationship between the sensor measurement value and the
two parameters is as follows:
Conductivity measurement = (original measurement + deviation) * factor
Two-point calibration requires the preparation of two water samples with known conductivity
values. The calibration process is as follows:
Use the 06 function code to write the value 33 to the No. 33 register to restore the
calibration;
Put the sensor into the water sample 1, and gently shake the sensor to ensure that no air
bubbles affect the measurement at the measuring end of the sensor. After the value is
stable, record the measured 1;
Rinse the sensor with pure water and absorb the residual moisture with filter paper. Put
the sensor in water sample 2 and shake the sensor gently. After the value is stable,
record the measured 2;
Calculate the deviation value and factor value
Factor = (water sample value 2-water sample value 1) / (measured 2-measured 1)
Deviation value = (water sample value 1 / factor )-measured value 1
Use the 16 function code to write the deviation value and factor value into the
corresponding register

- 6 -
Use
4.3.2 Multi-point Calibration
Multi-point calibration requires preparation of four standard solutions: 84uS, 146uS,
1413uS, and 12880uS. The calibration process is as follows:
Use deionized water to clean the electrode and absorb the residual moisture with filter
paper. Place the electrode in dry air and wait for the measured value to stabilize. Use
the 16 function code to write a value of 0 to the 23 register;
Use deionized water to clean the electrode and absorb the residual water with filter
paper. Place the electrode in the 84uS/cm conductivity standard solution, wait for the
electrode measurement to stabilize, use the 16 function code, and write the value 84
to the 25 register;
Use deionized water to clean the electrode and absorb the residual moisture with filter
paper. Place the electrode in the 146uS/cm conductivity standard solution, wait for the
electrode measurement to stabilize, use the 16 function code, and write the value 146
to the 27 register;
Use deionized water to clean the electrode and absorb the remaining moisture with
filter paper. Place the electrode in a 1413uS/cm conductivity standard solution, wait for
the electrode to measure stable, use the 16 function code, and write the value 1413 to
the 29 register;
Use deionized water to clean the electrode and absorb the residual water with filter
paper. Place the electrode in the 12880uS/cm conductivity standard solution, wait for
the electrode to measure stable, use the 16 function code, and write the value 12880
to the 31 register;
Note: When calibrating, it is recommended to calibrate at 25°C, otherwise a small amount of
temperature compensation error will be introduced.
Tip: The sensor supports up to 5 points of calibration, and the user can select the calibration point
according to the application.
4.3.3 Temperature Correction
Temperature correction provides the function of adjusting temperature deviation. The
calculation method of temperature deviation is as follows:
Temperature deviation value = actual temperature value-temperature measured
4.3.4 Reset Calibration
Use the function code 06 to write the value 33 to the No. 33 register to restore the sensor
calibration parameters to the factory state.

- 7 -
Maintenance work
Maintenance frequency
Visual inspection
Every month
Check calibration
Monthly (according to the environmental conditions of use)
Maintenance
Chapter 5 Maintenance
The sensor contains precision photoelectric components. Please make sure that the sensor will
not be subject to any strong mechanical impact during use. There are no user maintenance
parts inside the sensor.
5.1 Maintenance Cycle
5.2 Cleaning
During routine cleaning, the sensor can be cleaned by shaking it in clean water. If the surface
of the sensor measuring part is seriously polluted, the sensor measuring part can be soaked
in light detergent or weak acid for 15 minutes, and then the electrode can be cleaned with
distilled water.
Note: During installation and cleaning, do not use hard objects to touch the surface of the measurement
electrode, let alone wipe the surface of the electrode with any objects, otherwise the measurement will be
inaccurate and need to be recalibrated, which will affect the measurement range of the sensor in severe
cases.

Item
Register
Data Type
Length
Access
Type
Function
Code
Description
State
0
Unsigned
integer
1
Read
04
Non-zero means the sensor is
performing calibration
Conductivity
measure
2
Floating point
2
Read
04
Output value unit:uS/cm
Temperature
measure
4
Floating point
2
Read
04
Temperature measurement value,
unit: ℃
Salinity value
6
Floating point
2
Read
04
Calculated value of salinity, unit: ppt
TDS value
8
Floating point
2
Read
04
TDS calculated value, unit: ppm
Serial number
10
String
6
Read
04
Serial number 12-bit ASCII code
Firmware version
16
Unsigned
integer
1
Read
04
version number x100
Address
0
Unsigned
integer
1
Read/write
03/06
Communication address range 1~254,
default 17
Baud rate
1
Unsigned
integer
1
Read/write
03/06
0=4800,1=9600(default),
2=19200,3=38400
Check Digit
2
Unsigned
integer
1
Read/write
03/06
0=no (default), 1=Odd, 2=Even
Stop bit
3
Unsigned
integer
1
Read/write
03/06
1=1STOP (default) ，2=2STOP
Average times
4
Unsigned
integer
1
Read/write
03/06
0=2 times (default), 1=4 times,
2=8 times, 3=16 times, 4=32 times
Range setting
5
Unsigned
integer
1
Read/write
03/06
0=auto (default), 1=20uS/cm,
2=200uS/cm, 3=2000uS/cm,
4=10000uS/cm
Temperature mode
6
Unsigned
integer
1
Read/write
03/06
0=auto, 1=manual
Conductance
deviation
7
Floating point
2
Read/write
03/16
Deviation value default 0.0 uS/cm
Conductivity factor
9
Floating point
2
Read/write
03/16
Factor correction default value 1.0
Manual temp value
11
Floating point
2
Read/write
03/16
Default 25℃
Temp deviation
13
Floating point
2
Read/write
03/16
temp deviation value default 0.0℃
Cell constant
15
Floating point
2
Read/write
03/16
Default 1.0
TDS Conversion
factor
17
Floating point
2
Read/write
03/16
Default 0.5
Temp
Compensation
Coefficient
19
Floating point
2
Read/write
03/16
Default 1.85%/℃
Appendix
Appendix A Modbus Register Information

Item
Register
Data Type
Length
Access
Type
Function
Code
Description
Zero point CAL
21
Floating point
2
Write
03/16
Write 0 to perform zero point calibration
Point 1st CAL
23
Floating point
2
Read/write
03/16
Write the calibration solution value to
start calibration, 84uS/cm
Point 2nd CAL
25
Floating point
2
Read/write
03/16
Write the calibration solution value to
start calibration, 146uS/cm
Point 3rd CAL
27
Floating point
2
Read/write
03/16
Write the calibration solution value to
start calibration, 1413uS/cm
Point 4th CAL
29
Floating point
2
Read/write
03/16
Write the calibration solution value to
start calibration, 4239uS/cm
Point 5th CAL
31
Floating point
2
Read/write
03/16
Write the calibration solution value to
start calibration, 12880uS/cm
Reset CAL
33
Unsigned
integer
1
Write
06
Write 33 to resume calibration
Appendix
Note 1: When the parity bit is set to "None", the stop bit can be set to 1STOP/2STOP; when the parity bit is set to "Odd"
or "Even", the stop bit can only be set to "1STOP".

Delfino Environmental Technology Co., Ltd.
www.daruifuno.com
[email protected]