Operating Manual for BMET-202

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1. Introduction
    1.1 Introduction
    1.2 Technical Specification
    1.3 Function Introduction
2. Safety Notices
3. Terms Explanation
4. Overview and Installation
    4.1 Overview
    4.2 Instrument Installation
5. Instrument Operation
    5.1 Switch On/Off
    5.2 Screen Icons
    5.3 Function Key
    5.4 Instrument Settings
    5.5 pH Measurement
    5.6 Data Management
6. Maintenance/Troubleshooting
    6.1 Meter Maintenance
    6.2 Electrodes Maintenance
    6.3 Troubleshooting
7. Technical Supports
8. Appendixes
    Appendix 1

1. Introduction

1.1 Introduction

BMET-202 portable pH meter is a newly designed functional instrument that can be widely used in universities, environmental protection, medicine, food, sanitation, geological prospecting, metallurgy, ocean exploration and other fields measurements for acid rain detection, industrial wastewater, surface water, drinking water, beverages, daily chemical products, textiles and other related industries.

General Features
- High resolution LCD display, 5.7 inches.
- Multi-reading
- feature
- allows
- auto-read,
- timed-read and continuous-read.
- Automatic/Manual temperature compensation ensures accurate results.
- Auto-hold feature senses and locks the measurement endpoint.
- Data storage 500 sets (GLP-compliant).
- Support for USB or RS-232 communication.
- Reset feature automatically resumes all settings back to factory default options.
- IP54 waterproof.
- 1-5 points calibration with standard recognition.
- Selectable pH buffer groups, including NIST, DIN, GB, USA.
- Automatic electrode diagnosis with pH slope and offset display.

1.2 Technical Specification

Table 1-1 Technical Specifications

Model		BMET-202
pH level		0.01pH
mV	Range	(-2000.0～2000.0)mV
	Minimum resolution	0.1mV
	Electronic unit indication error	±0.1% or ±0.3mV
	Electronic unit repeatability	1mV
	Electronic unit input current	≤1×10-12A
	Electronic unit input impedance	≥1×1012Ω
pH	Range	(-2.00～20.00)pH
	Minimum resolution	0.01pH
	Electronic unit indication error	±0.01pH
	Electronic unit repeatability	0.005pH
	Instrument indication error	±0.02pH
	Instrument repeatability	0.01pH
Temperature	Range	(-5.0～110.0)°C
	Minimum resolution	0.1°C
	Electronic unit indication error	±0.2°C
	Instrument indication error	±0.4°C (0°C -60°C) ±1.0°C (Other range)
Use environment		Environment temperature：(0～40)°C Relative humidity: not more than 85%
Dimensions(L×B×H), Weight(kg)		242mm×195mm×68mm ，0.9kg
Power supply		Power adapter, Input: AC100～240V Output: DC9 V

1.3 Function Introduction

Table 1-2 Functions Specification

Features		Explanation
Basic Function	Languages	English
	Backlight adjustment	●
	Automatic diagnostics	●
	Reset settings	●
	Default parameter	●
	Prompt Sound	●
	Time settings	●
	Power failure protection	●
	Firmware upgrade	●
	Anti-interference automatic recovery	●
	Automatic shutdown	●
	Protection	IP54
Reading Function	Reading balance settings	●
	Auto-lock reading	●
	Reading Mode	Continuous, Auto, Timed
	Sample ID	●
Data Management	Storage	500 sets
	View	●
	Delete	●
	GLP	●

Features		Explanation
Communications and external devices	Printer	RS232 Serial Printer
	Content and format customization	GLP, Standard, custom
	PC	●
pH/mV Measurement	pH electrode status/performance	Slope, Electrode status
	Multi-point calibration	5 points
	Automatic standard solutions recognition	4 Group
	Standard solutions customization	●
	Standard groups customization	1 Group
	Automatic temperature compensation	●
	Manual temperature compensation	●
	pH electrode diagnostics	●
Temperature Measurement	Temperature units	°C , °F

2. Safety Notices

Please read the entire contents of this manual carefully before use, and please keep this manual properly. The user must use the instrument following this manual to avoid damage to the user and equipment.

Before using the meter, READ the following notes:
- DO NOT DISASSEMBLE the device for inspection or repair.
- To prevent electric shock or damage to the device, DO NOT place cables and connectors in any liquid, wet or corrosive environment.
- Please use the defaulted power adapter, DO NOT use it if the power cord is damaged (the wire is exposed or broken).
- DO NOT use in flammable and explosive environments.
- DO NOT use if the user finds any abnormalities such as damage or deformation of the device.

The following identifiers will be used in this manual.

3. Terms Explanation

- pH Slope : The amount of potential change generated by each 1 pH change, expressed in mV/pH or by 100% Theoretical Slope (PTS). pH = - log[H], where [H] means molar concentration (mol/L) of H ions.
- E0 of pH : Also known as "zero potential”, it usually refers to the potential value at a pH of 7.
- One-point calibration : Calibration with a standard solution.
- Two-point calibration : Calibration with two standard solutions.
- Multi-point calibration : Calibration with more than two standard solutions.

4. Overview and Installation

4.1 Overview

Figure 4-1 Overview-Front view

Figure 4-2 Overview- Back view

Figure 4-3 Electrodes and connectors

4.2 Instrument Installation

4.2.1 Electrodes Stand Installation

1. Pull out the electrode holder fixing plate on the right side of the instrument.
2. Press the electrode holder support onto the vertical shaft of the electrode holder drawer.
3. Tighten the set screw at the bottom of the electrode holder support.

4.2.2 Electrodes Connection

1. Mount the pH electrode (15) on the electrode holder (5).
2. Find the measuring electrode socket (9) on the back of the instrument, unplug the Q9 short circuit plug (18), then, insert the pH electrode into the measuring electrode socket (9).
3. Insert the other four-pin aviation of the pH electrode into the temperature electrode socket on the back of the instrument.
Figure 4-4 Electrode stand installation

5. Instrument Operation

5.1 Switch On/Off

After connecting the power adapter, the electrode holder and electrode, press and release to switch on the meter. The startup screen shows software version and other related information. After the self-test program, the screen turns to the homepage and the meter is ready to measure.
The meter equipped with 8 function keys. Users press and hold the key for more than 3 seconds and release to shut down.

5.2 Screen Icons

Figure 5-1 Screen icons explanation

1 Title. 2 System time. 3 Measurement parameters and balance status.4 Main measurement box.5 Calibration information. 6 User ID. 7 Sample ID. 8 Operation tips. 9 Soft function keys.

The instrument displays symbol identification that has the following functional implications:
Table 5-1 Symbol explanation

No.	Symbol	Explanation
1		Reading status, display the measurement status of reading, stable, locked each indicates that the processing, stable, and reading completed.
2		The percentage slope of the pH electrode calibration data
3		The standard buffer solution for calibration
4		Time to Calibrate Electrodes
5		Standard solution for pH electrode calibration
6		Automatic temperature compensation
7		Manual temperature compensation
8		User ID
9		Sample ID
10		Operation Tips

5.3 Function Key

Figure 5-2 The Screen and key

Table 5-2 Key function explanation

No.	Keys	Explanation	Note
1		Power	Press to switch on/off
2		Setting	Set the parameters and settings
3		Cancel	Cancel the operation
4		Enter	Confirm the option
5		F1	Function key, Corresponds to the function options on the screen
6		F2	Function key, Corresponds to the function options on the screen
7		F3	Function key, Corresponds to the function options on the screen
8		F4	Soft function keys, corresponding to the functions on the screen

5.4 Instrument Settings

In the standby interface of the instrument or during the measurement process, you can set the instrument parameters through the soft function key "Setting".

5.4.1 Tutorial settings

For the first use, please follow the guide to settings the measurement parameters. After all the settings, press the "Enter" to return to the previous page.

5.4.2 Reading Mode Settings

The meter provides three reading modes, including continuous readings, auto readings, and timed readings.
- Continuous reading: The instrument displays real-time measurement results. User can end the measurement at any time and save the last result.
- Auto-reading: The measurement reached the balance, and the meter locked the reading result. The meter offers "Fast", "Medium”, “Strict" and "Custom" four options for endpoint detection conditions.
- Time reading method: Timed Reading contains two kinds of timed reading methods: "Interval Measurement" and "Timed Measurement". "Interval Measurement" provide measurement results at interval time and "Timed Measurement" provide measurement result after a set time.

Table 5-3 Reading parameters settings

Stability Type		pH
Fast	Stable time	4s
	Fluctuation	1mV
Medium	Stable time	6s
	Fluctuation	0.5 mV
Strict	Stable time	8s
	Fluctuation	0.1mV
Custom (Recommended value)	Stable time	1 to 30s
	Fluctuation	0.1~1mV

5.4.3 pH Parameter Settings

5.4.3.1 pH standard groups

The pH electrode needs to be calibrated with a pH standard buffer solution, and different countries and regions often use pH standard buffer solutions prepared with different standards. For the convenience of your use, the instrument has built-in three commonly used standard solutions including GB, DIN and NIST. You can choose according to the actual situation. The instrument also supports the construction of custom standard solution groups. You can select the required standard solution from the standard buffer solution library to form a custom standard solution group.

Table 5-4 Standard solution groups

Groups	Contents
NIST	1.68pH, 4.01pH, 6.86pH, 7.00pH, 7.42pH, 10.01pH, 12.47pH
USA	1.680pH, 4.010pH, 7.000pH, 10.010pH
DIN	1.68pH, 2.00pH, 3.56pH, 3.78pH, 4.01pH, 6.87pH, 7.00pH, 7.42pH, 9.18pH, 10.01pH, 12.45pH
GB	1.68pH, 3.56pH, 4.00pH, 6.86pH, 7.41pH, 9.18pH, 12.46pH

Figure 5-3 Selection of standard groups and standard solution

After selecting the standard solution group, we need to select the standard buffer solution used for calibration from the standard solution group. The instrument supports up to 5-point calibration, that is, up to 5 standard solutions can be selected. Since the pH values of multiple standard buffer solutions in the standard solution group may be very close, to ensure that the instrument can correctly identify the standard buffer solution, will limit the selection of standard solutions with neighboring pH values. The check mark indicates the currently used standard solution group and the corresponding standard solution.


5.4.3.2 Recognition
In some special cases, it is necessary to use some non-standard pH buffer solutions, or use two very close pH standard buffer solutions for electrode calibration. In this case, the manual standard solution identification function can be used. When set to "Manual Mode", the pH value of the current standard solution can be input during and used for electrode calibration.

5.4.3.3 Resolution setting The pH measurement resolution of the instrument is adjustable.
pH resolution: 0.01pH and 0.1pH.
mV resolution: 0.1 mV and 1 mV.

5.4.4 Temperature Parameter Settings

The temperature unit of the meter is selectable in °C and °F. Temperature compensation mode: ATC and MTC.
ATC means automatic compensation. MTC means manual compensation.
It allows user to input the temperature.

5.4.5 Data Management Settings

5.4.5.1 Sample ID type

The instrument supports three setting methods of Sample ID: number order, time order, and manual.
- Number order: The sample ID No. is increasing with series number.
- Time order: The sample ID No. is increasing with sample measuring time. Format: Year/Y, Month/M, Day/D, Hour/H, Minutes/M, Second/S
- Manual: Manually set the sample ID No. It allows samples to manually enter the sample ID when saving or printing data.

5.4.5.2 Result Autosave
When this function is enabled, the meter saves the results when the reading is stable in the auto-reading and interval timed reading mode.

5.4.5.3 Data Overwrite
The meter provides 500 sets of measurement results storage space. When this function is enabled, the results data that exceeds capacity will be overwritten the old results data.

5.4.6 Output option

The data format is GLP, STD Format, and Custom. It could select one data format to output the result. data format to output the result.

5.4.7 User ID Settings

Set the user ID.

5.4.8 System Parameter Settings

5.4.8.1 System Date & Time
Settings of system date and time.

5.4.8.2 Buzzer setting
Users can set the key sound by this setting.

5.4.8.3 Brightness setting
Users can adjust the screen brightness by this setting.

5.4.8.4 Auto Power off
The meter provides auto shutdown function. When the meter is not using, the meter switches off automatically.

5.4.8.5 Restore Default
The meter supports "Restore Default" and "Restore Parameters". "Restoring Default" will restore all meter parameters to the factory state. "Restoring parameters" will restore the measurement parameters to the factory state.

5.4.8.6 Software version
Users can find the software version information on the general setting page.

5.5 pH Measurement

5.5.1 Calibration Preparation

The electrode slope and zero potential of pH electrodes drift slightly over time. To accurately measure pH, it is recommended to calibrate the pH electrode before use, the instrument supports 1–5-point calibration.

One point calibration is a calibration process with a single standard solution, commonly applied in a quick test. The calibration slope is 100% in here.

Two-point calibration is to use two pH standard buffer solutions to calibrate the electrode, and construct a linear calibration curve through two points. Two-point calibration is the most commonly used calibration method, and it is usually recommended that the pH value of the solution to be measured lies between the two standard buffer solutions. Two-point calibration can improve pH measurement accuracy.

Multi-point calibration is a calibration process with more than one standard solution. It is recommended to calibrate between two standard buffer solutions at the pH of the solution to be tested. Multi-point calibration covers a wider measurement range for accurate pH measurement. Before starting calibration, please prepare one or more pH standard buffer solutions.

5.5.2 Standards group selection

Before starting calibration, please prepare one or more pH standard buffer solutions. The meter has standards recognition function. Please set the Standard Group before the measurement.
You can also set the identification type to "Manual Mode" and manually enter the nominal value during the calibration process.

5.5.3 pH Calibration

The calibration process is as follows:
1. Setting.
- Set the parameters (e.g. pH).
- Select NIST standard solution group, and check pH 4.01, pH 7.00 and pH 10.01 three standard solutions.
- Set the Auto Mode recognition.
- Connect the ATC probe or enter the temperature manually.

2. Press the F2 "Calibrate" for one-parameter measurements or press the F2 "Calibrate"-"pH Calibration" for multi-parameter measurements.
3. Put the cleaned electrode into pH 4.01 standard solution.
4. Wait for the instrument to display “Auto Mode Matched”, press the F4 “Start”.
5. If only 1-point calibration is required, after 1-point calibration is completed, press the "Enter" key to complete the calibration.
6. If multi-point calibration is required, please replace the pH7.00 and pH10.01 standard buffer solutions. After cleaning the electrode, put the electrode into the standard solution. After the instrument recognizes it successfully, the instrument reads stably, press the F4 "Next Point" to complete the calibration.
7. After completing the calibration, press the "Enter" key to complete the calibration, save the calibration results and end the calibration, directly enter the start interface. If the checked standard solution group is 5, automatically end the calibration after five points of calibration.

Figure5-4 pH electrode calibration information

5.5.4 pH Measurement

The measurement process is as follows:

1. Setting.
- Set the parameters (e.g., pH).
- Set the reading mode (e.g., continuous reading, auto-reading, or timed format).
- Put the electrode into test solution under test.
- In the idle status, press F4 "Measure" to enter into measurement status.
- When the reading is stable, press "Enter" to read the results.
- Press the "Save" to save the measurement results.
- Press the "Output" to print the measurement result when connect to the printer.
- Between measurements, stored pH electrode in distilled or deionized water.
- After measurement, rinse the pH electrode with deionized water thoroughly.

Figure 5-8 pH measurement information

5.6 Data Management

Press "Data" to view the detail of results.
The meter stores the measurement results independently according to the measured parameters. The meter provides data Storage 1000 sets for each parameter (pH/pX/ISE/EC/Resistivity/TDS/Salinity/DO/Saturation).

The user can press "Delete" into the delete menu. It allows users to select the current data or all data to delete.

The user can view the data filter by parameter, locate No. or stored date. By the filter setting, press "Start Search" to look up the data. The filter data shows in a graph. Press "←" and"→" to choose data. User can choose one and press "Enter" key to see the detail result. Users can press "Delete" to delete the current result. Press "Output" to select the output data. The format supports output the current result, output matched result and output all result.
Figure 5-16 Results setting view

Fig 5-16 Review the stored resulted by graph



The format is roughly as follows:

6. Maintenance/Troubleshooting

6.1 Meter Maintenance

The correct use and maintenance of the instrument can ensure the accurate and reliable performance of the instrument. Maintenance plays an important role in pH measurements, which have high input impedance and are susceptible to damage from static electricity and electromagnetic field disturbances. Additionally, exposure to chemicals or harsh use environments can affect performance.

When the pH measuring electrode socket is not connected to the electrode, please insert the Q9 short-circuit plug to prevent the meter from being damaged. Please place the Q9 short-circuit plug in a dry and clean environment to prevent the short-circuit plug from being corroded to affect the short-circuit effect.

If the instrument is not used for a long time, please disconnect the power supply.
Keep the meter and accessories clean and away from acids, alkalis, and any corrosive solutions/gases.

The housing material of this meter is sensitive to certain organic solvents such as toluene, xylene, and methyl ethyl ketone (MEK). If liquid enters the housing, it may damage the instrument. Users can clean the meter surface with poor waters and detergent.
- Unplug the meter and remove all connected cables.
- Remove the electrode holder.
- In order to avoid damage to the meter during long-distance transportation, please try to use the original packaging.

6.2 Electrodes Maintenance

Before using the electrode, you should read the electrode manual carefully to understand the type, structure and application scope of the electrode.
For more details, please refer to the electrode instruction manual.

6.3 Troubleshooting

Table 6-1 Troubleshooting

Phenomenon	Probable reasons	Solutions
1. No Display	1. Damage to the meter.	1. Connect the adapter and press the power key to turn it on, replace or repair as required.
2. Incorrect mV measurement	The electrode is out of service life. The connector is in poor contact.	Replace the electrodes Connect the protection plug, if the potential is not 0mV, please contact the after-sales service.
3. Incorrect pH measurement	Refer to as 2.1. Refer to as 2.2. The electrodes are not calibrated or are calibrated incorrectly.	Refer to as 2.1 Refer to as 2.2 Re-calibrate the electrode or replace the standard solution

If the meter still does not work, please contact your local dealer for further assistance.

7. Technical Supports

Accessories
Please refer to the accessories table for purchasing recommendations.
Table 7-1 Meter accessories

Name	Description
E-301-QC 3 in 1pH composite electrode	pH Measurement Probe
Standard pH buffer solution 4.01/7.00/10.01	Standard solution

8. Appendixes

Appendix 1

pH-Temperature Relationship Table of pH Standard Solutions

Temperature(°C)	1.68	4.01	7.00	10.01
5	1.67	4.00	7.09	10.25
10	1.67	4.00	7.06	10.18
15	1.67	4.00	7.04	10.12
20	1.68	4.00	7.02	10.06
25	1.68	4.01	7.00	10.01
30	1.68	4.01	6.99	9.97
35	1.69	4.02	6.98	9.93
40	1.69	4.03	6.97	9.89
45	1.7	4.04	6.97	9.86
50	1.71	4.06	6.97	9.83