8KBB Mass Flow Meter Modbus485 Version Overview
8KBB mass flow meter adopts Modbus485 communication protocol, suitable for high-precision mass flow measurement in industrial process control. This manual version is for the RS-485 interface, supporting remote configuration and data acquisition, facilitating integration into DCS or PLC systems.
The flow meter is based on the Coriolis force principle, directly measuring mass flow, unaffected by temperature, pressure, or viscosity changes. The Modbus485 version provides standard register mapping for secondary development.
Download 8KBB Chinese Manual.pdf
Product Features and Core Parameters
Main Technical Features
- High-precision measurement: Mass flow accuracy up to ±0.2%, repeatability better than ±0.1%.
- Multi-parameter output: Simultaneously measures mass flow, volumetric flow, density, and temperature.
- Modbus485 communication: Supports RTU mode, adjustable baud rate, half-duplex.
- Wide turndown ratio: Typical turndown ratio 100:1, adaptable to various working conditions.
- Rugged design: Stainless steel housing, IP67 protection rating, suitable for harsh environments.
Key Performance Parameters
| Parameter | Specification | Remarks |
|---|---|---|
| Mass flow accuracy | ±0.2% | Percentage of reading |
| Repeatability | ±0.1% | — |
| Medium temperature range | -50°C ~ +200°C | High-temperature model optional |
| Ambient temperature | -40°C ~ +60°C | — |
| Output signal | 4-20mA, pulse, Modbus485 | — |
| Power supply | 24VDC ±10% | Typical |
| Protection rating | IP67 | — |
Modbus485 Communication Configuration
Communication Parameter Settings
The default communication parameters of the 8KBB mass flow meter Modbus485 version are as follows, and can be modified via hand-held communicator or host computer. Ensure the master and slave parameters match.
- Protocol: Modbus RTU
- Baud rate: 9600 bps (default), optional 19200, 38400, 115200
- Data bits: 8 bits
- Stop bits: 1 bit
- Parity: None (default), optional odd, even
- Slave address: 1~247 (default 1)
Register Mapping Table
The following are common register addresses, supporting function codes 03 (Read Holding Registers) and 06 (Write Single Register). All data are 16-bit integers and need scaling conversion.
| Register Address | Name | Data Type | Unit | Read/Write |
|---|---|---|---|---|
| 0x0000 | Mass flow instantaneous value | INT16 | 0.1 kg/h | R |
| 0x0001 | Mass flow total value high word | INT16 | — | R |
| 0x0002 | Mass flow total value low word | INT16 | — | R |
| 0x0003 | Medium temperature | INT16 | 0.1 °C | R |
| 0x0004 | Density | INT16 | 0.001 g/cm³ | R |
| 0x0010 | Slave address | INT16 | — | R/W |
| 0x0011 | Baud rate setting | INT16 | — | R/W |
Installation and Wiring Guide
Installation Steps
- Ensure the pipeline is stress-free, the flow meter flange is coaxial with the pipeline, avoiding installation stress affecting measurement accuracy.
- Install according to the flow direction arrow, ensure the medium fills the pipeline; for liquids, low inlet and high outlet is recommended.
- Tighten the flange bolts in a diagonal sequence gradually to prevent leakage.
- Connect power and communication lines, note polarity: RS-485 A to A, B to B, shield single-point grounding.
- After power-on, check the indicator status; during normal operation, the green light is steady on, flashing during communication.
Wiring Definition
| Terminal No. | Function | Recommended Wire Color |
|---|---|---|
| 1 | 24VDC+ | Red |
| 2 | 24VDC- | Black |
| 3 | RS-485 A | Yellow |
| 4 | RS-485 B | Blue |
| 5 | Shield ground | Shield mesh |
Common Troubleshooting
Communication Faults
- No communication: Check if slave address, baud rate, parity match; check if A/B lines are reversed.
- Data error: Check if register address is correct; confirm data format (INT16/floating point).
- Unstable communication: Add termination resistor (120Ω); shorten communication distance or lower baud rate.
Measurement Faults
- Flow shows zero: Check if pipeline is full; confirm valve is open; check sensor wiring.
- Large measurement fluctuation: Eliminate pipeline vibration; check if medium contains gas; confirm good grounding.
- Abnormal density: Check if medium temperature exceeds limit; recalibrate density coefficient.
For more detailed instructions, please refer to the 8KBB Chinese Manual.pdf, or contact the manufacturer's technical support.