The water meter adopts the photoelectric direct reading technology to read the word wheel data. Compared with the traditional pulse meter, it can reduce the reading error to zero. It is an electronic remote water meter with zero error of electromechanical conversion in the automatic meter reading system, and adopts low-power design. It usually does not need power supply, and it needs to be powered only when reading the meter or valve.
The photoelectric direct reading valve controlled water meter adopts rotor metering structure, which has the characteristics of high metering accuracy, small starting flow, convenient meter reading, beautiful appearance, safety and health, long service life and so on.
The photoelectric direct reading valve controlled water meter cooperates with the intelligent meter reading system equipment to complete the intelligent reading of the water, electricity and gas meter data of the community, and realize the network data sharing with the settlement center.

I. Product Characteristics
Compared with the traditional pulse meter, it can reduce the reading error to zero;
Low power consumption design is adopted, and power supply is required only when reading and valve switching;
Advanced data coding and verification technology is adopted, with high communication reliability;
Rotor type metering structure is adopted, with high metering accuracy, convenient meter reading and beautiful appearance;
Compatible with multiple communication protocols; DL / T645, CJ / T188 and internal protocols;
Meet the design requirements of EMC, ESD, EMI and other electronic products, and reach the industry-leading level;
Combined with the host computer system, a remote automatic meter reading management system is established to truly realize the automation of meter reading and monitoring.
Short circuit current protection;
For bus open circuit, short circuit, idle and other fault protection.

II. Technical parameters
Product model: lxsxy-15 / 20;
Working voltage: MBus interface DC 36V; RS485 interface DC12V
Operating current:
   meter reading working current ≤ 2.5mA
   static working current ≤ 1.3 Ma
Working environment: water temperature: 0.1 ℃ ~ + 45 ℃, humidity: 0 ~ 95% RH;
Storage temperature: - 25 ℃ ~ + 65 ℃;
Maximum allowable water pressure: 1 MPa;
Maximum pressure loss: 0.063 MPa;
Communication mode with host computer: M-BUS or RS485;
Communication transmission rate: 2400 baud;
Communication protocol: DL / T645 or CJ / T 188;
Maximum communication transmission distance: 300m; (communication line specification avvr2) × 0.75）
Opening / closing time of single meter valve: 15s;
ESD protection of bus pin exceeds 10kV;

III. Flow parameters

Water Meter Model	Nominal Diameter  DN (mm)	Accuracy class	Overload flow Q4	Common Flow Q3	Boundary flow Q2	Minimum flow Q1
			m³/h
LXSXY-15	15	2	3.125	2.5	0.050	0.030
LXSXY-20	20	2	5.00	4.0	0.080	0.050

Overload flow (Q4) - it is required that the water meter can meet the maximum allowable error requirements in a short time, and then maintain the maximum flow of metering characteristics under rated working conditions;
Maximum flow (Q3) - the maximum flow under rated operating conditions. Under this flow, the water meter shall work normally and meet the requirements of maximum allowable error;
Boundary flow (Q2) - the flow that occurs between the common flow Q3 and the minimum flow Q1 and divides the flow range into "high area" and "low area" with specific maximum allowable error;
Minimum flow (Q1) - the minimum flow that requires the indication of the water meter to meet the maximum allowable error.
Maximum allowable error:
The maximum allowable error in the low area from including the minimum flow (Q1) to excluding the boundary flow (Q2) is ± 5%;
The maximum allowable error in the high area including the boundary flow (Q2) to the maximum flow (Q4) is ± 2%.

IV. Installation Dimensions

Nominal diameter	Length L	LengthL L1	Breadth B	Height H	Connection threads		weight (copper shell)	Connecting line
mm					d	D	kg	m
DN15	258	165	85	116	R1/2	G3/4	1.4	0.8
DN20	298	195	85	116	R3/4	G1	1.7	0.8

V、 Installation, use and maintenance methods
1. The installation position shall be protected from exposure, freezing, pollution, humidity and flooding for easy disassembly and meter reading. During freezing, in addition to wrapping the water meter and water pipe, close the valve at the inlet end of the water meter and open the drain valve and faucet at the outlet end when not in use, so as to prevent the water meter from being damaged due to freezing expansion. It is recommended to install it in the special water meter box;
2. The water meter shall be installed horizontally, with the word facing upward, and the arrow direction is the same as the water flow direction;
3. When installing a new pipeline, be sure to wash the stones, sediment, hemp and other sundries in the pipeline before installing a water meter, so as not to cause water meter failure.
4. In order to measure accurately, the faucet shall be higher than the water meter.
5. The water meter shall not be directly connected with the pipeline. The water meter and the pipeline shall be connected through connecting pipe, sealing washer and connecting nut. When disassembling the water meter, do not force the hard board to avoid twisting the case.
6. The water meter shall not be subjected to excessive stress caused by pipes and fittings. If necessary, the water meter shall be installed on the base or bracket.
7. Valves shall be installed before and after the water meter to facilitate maintenance and replacement.

VI、Accessories
Each water meter is accompanied by 2 stainless steel pipe joints, connecting nuts and sealing rings, 1 certificate, and 1 product manual for each box.