model: SY889
Name: Bluetooth IC Card Smart Water Meter
Specifications: DN15\\DN20\\DN25
External dimensions:

Main functions:
1. Minimum consumption function
The module supports the minimum consumption function by cycle, settling based on water usage. When the monthly usage is below the set minimum consumption limit, the difference between the monthly usage and the set minimum consumption limit can be automatically deducted during settlement; When the monthly usage is greater than or equal to the minimum consumption limit, no additional deduction will be made.
The minimum consumption function can only be activated after opening an account and is consistent with the cycle of the ladder. It can be enabled or disabled through user card water purchases or rate setting cards.
When deducting the minimum consumption based on quantity, the amount of water that needs to be additionally deducted is not included in the cumulative and monthly usage, and the unit price of the deducted water usage is deducted using a 1-step unit price.
2. Ladder water pricing function
The module uses the amount as the settlement unit and can set settlement cycles of 1 month, 2 months, 1 quarter, 6 months, or 1 year. It can automatically settle according to the set steps and rate table based on the water consumption of each cycle.
The module supports 3 steps. Spare 1 set of rate table.
3. Measurement and prepaid functions
Adopting dual pulse sampling for measuring pulses, the two pulse sampling points are sequentially merged once to form a measuring signal of 0.1 m3. Compatible with reed switches and Hall sampling. According to the measurement signal, decrease the remaining amount in the table until the remaining amount is exhausted, and then close the valve. Simultaneously increase the monthly water consumption in the table and accumulate the water consumption.
4. Purchase water recharge
After the APP sends a recharge command, the water meter will add the current recharge amount to the original remaining amount. When the recharge is correct, the indicator light will turn on. When synchronizing the device, the new remaining amount and related information will be fed back and displayed on the APP interface.
5. Hoarding function
The water meter is set with a maximum storage limit. If the total amount of water purchased exceeds this limit when added to the remaining amount on the meter, the APP will prompt a recharge failure and indicate that the recharge limit has been exceeded; After waiting for the remaining amount in the table to accumulate with the water purchase amount and fall below the set maximum limit, the APP will send the recharge package again to complete the recharge.
6. Query function
The Bluetooth water meter APP can send query commands to return user information and meter related information, and display them in the APP.
7. Remaining amount alarm
When the remaining amount is less than or equal to the valve closing alarm amount, the valve will be closed to prompt the user to recharge. After synchronizing the APP device, the valve can be opened and the user will be prompted to pay in a timely manner.
8. Close the valve and pay the fee
The valve closing alarm amount can be set for the meter. When the remaining amount of the meter is less than or equal to the valve closing alarm amount, the meter will close the valve. At this time, the user can send a Bluetooth command through the "device synchronization" button on the Bluetooth water meter APP interface. The meter can restore water use and prompt the user to recharge and pay.
9. Low voltage protection function
The water meter usually measures the voltage once a day. When the meter detects that the battery voltage has been below 2.87V ± 0.05 for 12 consecutive days [with a certain load test], the valve will automatically close. Open the APP to synchronize the device and continue using the valve. The APP interface prompts the user to contact the management and replace the battery.. When the battery voltage is detected to be below 2.60V ± 0.05, the valve should be completely closed, and the user cannot open the valve. The user must notify the management department to replace the battery before continuing to use it.
10. Anti magnetic attack function
The water meter provides automatic protection function. When a magnetic field approaches, the valve will automatically close and the APP will prompt "sampling fault". Please check whether there are strong magnetic field objects or water immersion in the surrounding environment of the water meter. After processing, the device can synchronously open the valve. If it cannot be restored, the maintenance personnel can be notified to repair the water meter.
11. Table abnormality protection function
During normal use, if the valve of the water meter is closed and the synchronization device displays a fault prompt, please notify the maintenance personnel to repair the water meter as soon as possible.
12. Valve maintenance function
The valve is automatically maintained once every 15 days and is in a semi closed state.
13. Power on self-test
Power on the meter, perform self check on the status, detect the battery voltage, and automatically open or close the valve according to the specific situation of the meter.

Main technical parameters:
Applicable water temperature: Cold water gauge ranges from 0.1 ℃ to+40 ℃, hot water gauge ranges from+30 ℃ to+90 ℃
Applicable environmental humidity: ≤ 85%
Applicable pressure Pn: 0.03 MPa ≤ Pn ≤ 1.0 MPa
Pressure loss: ≤ 0.063MPa（Q3）
Static working current: ≤ 5 μ A (V=3.0V or 3.6V)
Main traffic parameters:

Explanation: The initial flow rate of the water meter is less than 0.002 m3/h
Maximum allowable error: from Q2 to Q4 ≤± 2%, from Q1 to Q2 (excluding Q2) ≤± 5%
Product Technical Standards: CJ/T133-2012, GB/T778-2018, and CJ266-2008
Bluetooth communication technology specifications:
Default transmission power: 0dBm (1.0mW)
Maximum transmission power: 4dBm (2.5mW)
Receiving sensitivity:- 96dBm 
Bluetooth communication peak power consumption: 6.5mA
Communication distance: (transmission power 0dBm, i.e. 1.0mW)
Indoor: about 10 meters Outdoor space: about 30 meters
Bluetooth module technical specifications:
Working voltage (MAX): 1.8~3.6V, the module cannot work below 1.8V.
Voltage alarm points: The first level voltage alarm point is around 2.9V, and the second level voltage alarm point is around 2.6V.
Static current: less than 4uA
Total average power consumption of the module: less than 20uA;
Working temperature: -20 ℃~60 ℃ Environmental humidity: 5%~85%
Supporting battery model: Supporting battery ER18505M (power type)