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  3. E1. Connection of the flow meter

E1. Connection of the flow meter

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1. Introduction

In this chapter we will cover:

  • Requirements for the cables
  • Requirements of the power supply
Never use the AC power! This will void the warranty and bring permanent damage to the electronics. The instrument might be damaged beyond repair.Icon no AC power

2. Overview M12 5-pin connector

Almost all connections are available via the M12 5-pin connector, located on the back of the Transmitter/display.

Transmitter back M5-pinVPFlowScope DP Display schematic side view



For use of Ethernet: use M12 4-pin connector, see chapter E4 Ethernet wiring.

The M12 5-pin connector:

Icon M12 5-pin

PinSignalWire color*
1+12..24 VDC.Brown
20 Volt.White
34..20 mA. signal, activeBlue

* Wire colors apply to VPInstruments cables.

3. Cabling details

For all connections!
Use: Shielded twisted pair cabling to avoid any interference from other outside electrical signals.Example twisted pair
Always: Connect the shield to safety ground at one point. When in doubt, ask an expert to help with proper grounding and shielding of your installation.Icon ground
Thickness of wires depends on the cable length:

  • Length < 300 m. / 1000ft : 20 awg
  • Length > 300 m. / 1000 ft: 18 awg or better

4. Power supply details

Input voltage: 12 to 24 VDC.

At the connector at least 12 Volt: be aware of the voltage drops over long cables!

Schematic Voltage drop


The Transmitter/display will notify you when there is insufficient power:

Schematic power insufficient

5. Next step

Your communication protocol defines the type of wiring you will need.

For RS485 communication go to ED2. RS485 Wiring
For analog output and communication go to E3. Analog output
Ethernet communication go to E4. Ethernet wiring
For only short-term measurement go to E5. Wiring for air audits


Updated on July 29, 2020

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