Modbus Smart Water Meter Communication Protocol Four Wires

Modbus water meter communication protocol

Introduction of RS485 module

Four wires: RS485 needs four wires, of which the second wire is rs485a, rs485b, the second wire is positive and negative 12V power line, the pulse signal line is not divided into positive and negative poles, and the 485 communication line is connected. Red (12V positive), blue (12V negative), yellow (485a), green (485b). Note: wiring must be done carefully! An error will result in damage to the instrument module.

The module integrates the pulse counting module, and outputs the accumulated pulse in RS485 or MBus mode, generally using RS485 Modbus communication protocol or 188 protocol.

When the communication line is long, the cross-sectional area of the communication wire should be increased, the communication line should avoid high-power electrical equipment and strong interference sources, and do a good job in waterproof protection.

Communication settings

1. Baud rate: 9600 / 4800 / 1200 (default 9600 cannot be changed)

2. Check: no check (default no check)

3. Data bit: 8

4. Stop bit: 1

Modbus Protocol

1. Read operation (03h)

2. Read operation reply(03H)

3. Write operation (06h)

4. Write operation reply(06H)

5. Write operation (10h)

6. Write operation reply (10h)

7. Exception code

8. Register address

Be careful:

The exception code is the highest bit plus 1 of the normal function code. For example, the exception code of the read operation 03h is 83h, the exception code of the write single word 06h is 86h, and the exception code of the write multiple word 10h is 90h.

The cumulative flow is a 4-byte hexadecimal number, with the high bit first and the low bit last. The cumulative flow uses 32-bit data (2 words) without sign.

For example, if the actual data is 123456, the high bit word is saved as 0x0001, and the low bit word is saved as 0xe240.

Unit of measurement: according to the ratio you write, this meter does not participate in the calculation, only records the actual pulse value.

For example:

Suppose the table address is 01 (table address range 1-247)

1. Write the base number of water meter 123456 (hexadecimal: 01e240h)

01 10 02 00 02 00 01 E2 40 73 86 13 bytes

Write the base number of water meter to return: 01 10 02 00 02 E1 B0 8 bytes

Exception: 01 90 03 0C 01 5 bytes (illegal data value)

2. Water meter reading: 01 03 02 00 02 64 73 8 bytes

Read Cumulative Return: 01 03 04 00 01 E2 40 E2 A3 9 bytes

Exception: 01 83 03 01 31 5 bytes

3. Reading water meter address: 00 03 02 00 01 84 63 8 bytes

Return: 01 03 02 00 01 79 84 7 bytes

be careful! When reading the water meter address, only one water meter can be connected to the bus.

MOQ:
We will accept your trial order or sample order.
Logo:
Customers could customize their logo or lable on the water meter.
Sample Policy:
We will send samples to you( by TNT or DHL or EMS) for your confirmation within 2-7 days after we come to an agreement.
Delivery time:
Start shipping within 10--25 days after signing the contract.
Payment terms:
L/C, T/T, Western Union, MoneyGram, Paypal.
Shipping:
We can arrange the shipping by Courier ( DHL, UPS, Fedex , TNT etc. ), by air or by sea for you.
List Of Competitive Advantage:
1. We are factory, can provide you high quality, best price
2. Professional employee and effective management
3. Professional trading service
4. Prompt delivery
5. Good service & reputation
6. Large production line

Yiwu dowler import and export company, founded in 2014, is an enterprise engaged in the production of smart home products, with its own independent design and development team. At present, the company mainly produces smart wall switches, smart on-off devices, smart temperature controllers, smart water meters, smart door locks and related smart home products. The products are sold all over the world and support domestic agent processing and import and export trade.