RS-485 ORP Probe POM AT-SB-PROBE-ORP-P
Datasheet
1. Introduction
SENSBLUE Monarch ORP Probe POM AT-SB-PROBE-ORP-P can be used for environmental water quality monitoring, acid/alkali/salt solution, chemical reaction process, industrial production process, and can meet the requirements of online ORP measurement for most industrial applications.
2. Features
- Signal output: RS-485 (Modbus/RTU protocol).
- Conveniently connect to third-party equipment such as PLC, DCS, industrial control computer, general controller, paperless recording instrument or touch screen.
- Double high impedance differential amplifier, strong anti-interference and fast response speed.
- Durable ORP electrode, the internal reference fluid seeps out from the microporous salt bridge very slowly under a pressure of at least 100KPa (1Bar), and its positive seepage lasts for more than 20 months. Such a reference system is very stable, and the electrode life is doubled compared to ordinary industrial electrodes.
- Easy to install: 3/4NPT pipe thread is convenient for sinking installation or installation in pipelines and tanks.
- IP68protection level.
- R-485 interface, Modbus/RTU protocol.
3. Technical Specifications
| Model | AT-SB-PROBE-ORP-P |
|---|---|
| Measuring Range | -1500～+1500mV |
| Accuracy | ±6mV |
| Resolution | 1mV |
| Temperature Range | 0 ~65℃ |
| Work Pressure | ＜0.1MPa |
| Output | RS-485, MODBUS protocol |
| Power Supply | 12～24VDC ±10% |
| Wetted Part Material | POM |
| Installation | Immersion mounting, 3/4 NPT thread |
| Cable Length | 15m |
| Calibration Method | One-point calibration |
| Power Consumption | ＜0.3W@12V |
| Ip Grade | IP68 |
4. Dimension
5. Installation and Electrical Connection
5.1 Install
Note: The sensor should not be installed upside down or horizontally when installed, at least at an angle of 15 degrees or more.
5.2 Electrical connection
- Red wire-power cord（12～24 V）
- Black wire-ground wire（GND）
- Blue Line-485 A
- White Line-485 B
Check the wiring sequence carefully before powering on to avoid unnecessary losses caused by wiring errors.
5.3 Wiring instructions
Considering that the cables have been immersed in water (including seawater) or exposed to air for a long time, all wiring positions are required to be waterproof, and the cables should have certain corrosion resistance.
6. Maintenance
6.1 Use and maintenance
When measuring the ORP electrode, it should be cleaned in distilled water (or deionized water) first, and the water should be absorbed with filter paper to prevent impurities from being brought into the test solution. 1/3 of the electrode should be inserted into the test solution. The electrode should be cleaned when not in use and inserted into a protective cover with 3.5mol/L potassium chloride solution or inserted into a container with 3.5mol/L potassium chloride solution. Check whether the terminal is dry, if it is stained, wipe it with absolute alcohol and blow it dry before use. Avoid long-term immersion in distilled water or protein solution and prevent contact with silicone grease. For electrodes that have been used for a long time, its glass membrane may become translucent or attached with sediment. In this case, it can be washed with diluted hydrochloric acid and rinsed with water. The electrode has been used for a long time, and when there is a measurement error, it must be calibrated and corrected with the meter. When the electrode is still unable to be calibrated and measured when the electrode is maintained and maintained by the above method, it means that the electrode has failed. Please replace the electrode.
6.2 ORP standard solution preparation method
a) Preparation method of ORP standard solution 256mV Weigh 2.1 g of quinhydroquinone and add it to 200 mL of a standard pH buffer solution with a pH of 4.00 and mix well.
b) Preparation method of ORP standard solution 86mV Weigh 2.1 g of quinhydroquinone and add it to 200 mL of a standard pH buffer solution with a pH of 6.86 and mix well.
c) Preparation method of ORP standard solution-40mV Weigh 2.1 g of quinhydroquinone and add it to 200 mL of a standard pH buffer solution with a pH of 9.18 and mix well.
Please note that when preparing the pH, a total of 250 mL is prepared, and 200 mL is measured for use.
Method of preparing corresponding standard solution for pH:
Measure 250mL of distilled water with a graduated cylinder, pour it into a beaker, add a package of calibration powder with pH=6.86/4.00/9.18, stir with a glass rod until the powder is completely dissolved, and prepare a solution with pH=6.86/4.00/9.18.
6.3 Calibration
Put the sensor into the prepared 86mV (or 256mV or-40mV) solution and wait for 3 to 5 minutes. After the value is stable, check whether the displayed value is 86mV (or 256mV or-40mV). If not, you need to calibrate it. See the appendix for calibration instructions.
6.4 Precautions
- Avoid exposing the inner surface of the fluorescent film head to sunlight
- Please do not touch the fluorescent film with your hands
- Avoid bubbles adhering to the surface of the fluorescent film during measurement and calibration
- Avoid applying any mechanical stress (pressure, scratches, etc.) directly to the fluorescent film during use
7. Appendix data communication
7.1 Data Format
The default data format for Modbus communication is: 9600, n, 8, 1 (baud rate 9600bps, 1 start bit, 8 data bits, no parity, 1 stop bit).
7.2 Modbus Frame Format (xx represents a byte)
a) Read data instruction frame
| 06 | 03 | xx xx | xx xx | xx xx |
| Address | FC | Register start address | Number of registers | CRC check code (low bytes in front) |
b) Read data response frame
| 06 | 03 | xx xx | xx xx | xx xx |
| Address | FC | Number of bytes | Response data | CRC check code (low bytes in front) |
c) Write data instruction frame
| 06 | 06 | xx xx | xx xx | xx xx |
| Address | FC | Register address | Read-in data | CRC check code (low bytes in front) |
d) Data response frame
| 06 | 06 | xx xx | xx xx | xx xx |
| Address | FC | Register address | Read-in data | CRC check code (low bytes in front) |
7.3 Register Address
| Register Address | Name | Instruction | Number of Registers | Access Method |
|---|---|---|---|---|
| 40001 (0x0000) | Measured value | Two double-byte integers are the measured value and the number of decimal places of the measured value. | 2 (4 bytes) | Read |
| 44097 (0x1000) | Zero calibration | Calibrate in the standard solution, the written data is the actual value of the standard solution. | 1 (2 bytes) | Write |
| 44103 (0x1006) | Zero calibration value | The read data is the zero offset. | 1 (2 bytes) | Read |
| 48195 (0x2002) | Sensor address | The default is 6, and the write data range is 1-127. | 1 (2 bytes) | Write/Read |
| 48225 (0x2020) | Reset sensor | The calibration value is restored to the default value, and the write data is 0. Note that the sensor needs to be calibrated again after reset before it can be used. | 1 (2 bytes) | Write |
| 44105(0x1008) | Slope calibration value | The read data is the slope value x1000 | 1 ( 2 bytes) | Read |
| 44113(0x1010) | Temperature calibration | Calibrated in solution, the data written is the actual temperature value x10 ; the read data is the temperature calibration offset x10 . | 1 ( 2 bytes) | Write/Read |
| 48195(0x2002) | Sensor address | The default is 6 and the data range is 1-127 | 1 ( 2 bytes) | Write/Read |
| 48225(0x2020) | Reset sensor | The calibration value is restored to the default value and the write data is 0. Note: the sensor needs to be calibrated again after resetting. | 1 ( 2 bytes) | Write |