Electrical Installation
Safety First: Do not perform wiring while the unit is powered on. Before any wiring work, turn off the power and disconnect the power supply.
CRITICAL WARNING: Do not apply overvoltage to communication lines The Modbus RS-485 communication lines (A/B) have a maximum rated voltage of typically 5 V. They must never be connected to or share continuity with the flowmeter's DC 24 V power lines. Incorrect wiring will instantly destroy the internal core components of the flowmeter. Damage caused by wiring errors is not covered under warranty. Always verify all wiring with a multimeter before powering on the device.
8-Pin Cable with Flying Leads Pin Definition
Connect the supplied cable to the power supply and the required communication interfaces.
Unused wires must be insulated with protective material to prevent electric leakage or short circuits.
Before opening the unit or performing any wiring, turn off the power and disconnect the power supply.
Due to space limitations, the label on the side of the unit and the following diagrams show wire pin definitions only.
The 8-pin wire color assignments are defined as follows:
Color
Function
Black
RS485 (B-)
Yellow
OCT output (-)
Blue
VDC (-)
Orange
OCT output (+)
Green
RS485 (A+)
Purple
4~20mA (+)
Red
4~20mA (-)
Brown
24 VDC (+)
White heat-shrinkable sleeve
(optional) Shielding net, please connect to ground.
DC Power Wiring Diagram
Brown Wire: 24 VDC (+)
Blue Wire: VDC (–)
4–20 mA Analog Output Wiring
Brown Wire: 24 VDC (+)
Blue Wire: VDC (–)
Purple Wire: 4–20 mA (+)
Red Wire: 4–20 mA (–)
This function requires the brown and blue DC power wires to be powered. The following diagram is not showing power supply wiring for readability.
OCT NPN Output Wiring Diagram
This function requires the brown and blue DC power wires to be powered. See the DC Power Wiring Diagram for details.
OCT PNP Output Wiring
Brown Wire: 24 VDC (+)
Blue Wire: 0 VDC (–)
Orange Wire: OCT Output (+)
Yellow Wire: OCT Output (–)
This function requires the brown and blue DC power wires to be powered. See the DC Power Wiring Diagram for details.
RS485 Two-Wire Wiring
Black Wire: RS-485 B (–)
Green Wire: RS-485 A (+)
This function requires the brown and blue DC power wires to be energized. See the DC Power Wiring Diagram for details.
RS-485 Wiring Recommendations
It is recommended to use shielded 24 AWG twisted-pair cable and connect devices in a daisy-chain configuration. Do not use star or ring wiring.
For long cable runs, install termination resistors at both the master and the farthest device. A typical value is 120 Ω, but the actual value should be calculated based on the cable specifications.
If signal instability occurs, consider adding bias resistors at a point along the line.
The 8-core cable is shipped with the device, if used in RS485 communication, please trim the length, try to use a short wire to reduce noise interference. Connect the shielding net to the main communication wire shielding and then ground it.
In areas with heavy signal interference, the software may need to poll multiple times to receive a response. Implement a repeated polling mechanism in the communication program to distinguish between signal interference and actual device offline conditions.
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