model: SY889
Name: Drinking Water IC Card Water Meter (M-Bus)
Specifications: DN15\\DN20\\DN25
Communication protocol: CJ/T 188-2004
External dimensions:

major function
1. Prepaid valve control function: "Pay first, use water later" solves the problem of difficult meter reading and billing for water companies, and eliminates the disturbance of household meter reading to residents.
2. The function of tiered water pricing: Three tiered water pricing and real-time deduction, "tiered water pricing" fully utilizes the role of market and price factors in water resource allocation, water demand regulation, and other aspects.
3. Preventing water hoarding function: Water companies can set recharge limits before raising prices to prevent users from maliciously recharging water bills before the increase. After recharging beyond the hoarding amount, users cannot recharge the water bill again, avoiding damage to the water company's economic interests.
4. Valve self maintenance function: The valve should be opened and closed once a month at 2:00 am on the 1st and 16th, which can prevent valve scaling and valve jamming caused by long-term inactivity of the water meter valve.
5. Remaining water low limit alarm function: When the remaining amount in the meter decreases to the alarm amount (set by the management department), the water meter will display the characters "close valve" and "please recharge", and the valve will automatically close, prompting the user to purchase water and recharge. At this point, the user can swipe the user card to open the valve and continue using water.
6. Card replacement function: If the user card is lost or damaged, the card replacement operation can be performed without any impact on the water meter installed in the user's home.
7. Table replacement function: The table replacement operation is very simple. With just one table replacement card, all the data from the old table can be imported into the new table without affecting user use, achieving zero disturbance for users.
8. Under voltage valve closing alarm function: The large capacity battery in the meter can be used for five years by the water meter. In case of special circumstances where the battery is depleted in advance, the low voltage indicator "" will flash on the screen for the first time, and the valve closing alarm will be displayed and executed. At this time, swipe the user card to open the valve. Low pressure was detected for the second time, and after the valve was closed, the "Power Shortage" sign was constantly displayed. Brushing the user card could not open the valve, and the water company could only be notified to replace the battery. This ensures that the user can use water normally without being unable to control the user's valve due to battery failure.
9. Magnetic interference attack valve closing alarm function: When the water meter detects strong external magnetism, it will immediately close the valve. Only when the strong external magnetism is cancelled can the valve be opened by jamming. If multiple strong magnetic interferences are detected, the water meter will completely close the valve to protect the interests of the water company.
10. Data storage function: In the event of a power outage, the data in the table will be saved for at least ten years, and the data will be automatically restored after being powered on again.
11. Display function: Dual display of water meter wheel and LCD.

Main technical parameters:
1. Applicable water temperature: Cold water gauge ranges from 0.1 ℃ to+40 ℃, hot water gauge ranges from+30 ℃ to+90 ℃
2. Applicable environmental humidity: ≤ 85%
3. Applicable pressure Pn: 0.03 MPa ≤ Pn ≤ 1.0 MPa
4. Pressure loss: ≤ 0.063MPa（Q3）
5. Static working current: ≤ 5 μ A (V=3.0V or 3.6V)
6. 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%
7. Product Technical Standards: CJ/T133-2012, GB/T778-2018, and CJ266-2008