SVF128 vortex flowmeter has 2 different terminal boards, the 5-terminals board, and the 12 terminals board, please refer to picture 3.1 and 3.2 below.

Picture 3.1: 5-terminals board

Picture 3.2: 12-terminals board

On the above boards, V+ and V- are for power. is a pulse output terminal. A, B are “+” and “-” for RS485Modbus communication, I+ and I- are + and – for 3-wire or 4-wire 4~20 mA.RT1, RT2, RT3 are for separate RTD. P+, P- is for pressure transmitter. SVF128 multivariable version has a built-in RTD and pressure sensor, so clients are not required to wire for temperature or pressure compensation.

3.1 Wiring for 5-terminal board

3.1.1 Wiring for 3 wire pulse output

3-wire pulse output requires a power source of 13.5~42VDC. SVF128 uses a current pulse output with a 50% duty ratio. If the pulse receiving instrument requires a voltage pulse, please add a resistor between “” and “V-”, the resistance should be within 500ohms~1000ohms, and power consumption should be no less than 0.5W.

Please refer to picture 3.3 picture below for 3-wire pulse output wiring.

Picture 3.3: 3-wire pulse output wiring

3.1.2 Wiring for 2 wire HART@4~20mA

When it is not temperate and pressure compensation and the power source is 24VDC, the max load for 4~20mA analog is 500ohms. And when it is temperate and pressure compensation and the power source is 24VDC, the max load for 4~20mA analog is 400ohms. When using a HART communicator, please add a 250ohms load resistor

Picture 3.4: Wiring for 2 wire HART@4~20mA

3.1.3 Wiring for RS485

Picture 3.5: Wiring for RS485

3.2 Wiring for 12-terminal board

3.2.1 Wiring for 3 wire pulse output

3-wire pulse output requires a power source of 13.5~42VDC. SVF128 uses a current pulse output with a 50% duty ratio. If the pulse receiving instrument requires a voltage pulse, please add a resistor between "" and “V-”, the resistance should be within 500Ω ~1000Ω, and power consumption should be no less than 0.5W.

Picture 3.6: 3-wire pulse output wiring

3.2.2 Wiring for 4 wire 4~20mA

Picture 3.7: Wiring for 4-wire 4~20mA

3.2.3 Wiring for 4 wire HART@4~20mA

When the power source is 24VDC, the max load for 4~20mA analog is 500Ω.

Picture 3.8: Wiring for 4-wire HART@4~20mA

Picture 3.9: Wiring for RS485

3.3 Shell grounding and elimination of interference

In the SVF128 digital vortex flowmeter, the power supply of the signal processing circuit is transferred from the outside power supply by an isolation-type DC-DC transmitter with advanced grounding technology. The field frequency interference can be isolated well.

When using this product, the “V-” of the power supplier should not be connected with the ground. When this product is used in an environment with strong interference, the shell should be connected with the earth through cable, so the interference can be eliminated.

3.4 Requirement on wiring

1. Please conduct wiring when the power is on in an explosive environment.
2. Please open the rear cover first, then insert the cable into the back zone of housing through the water-proof cable gland.
3. Conduct wiring according to 3.1 and 3.2.
4. If possible, please conduct the wiring according to picture 6.10 to avoid the water get into the housing through the cable.

Picture 3.10: Introduction for wiring