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Latest Vutlan drivers (from August 2021) support Modbus RTU read and write functions for all monitoring systems.

Physical description

VT336, VT855i, VT960i, VT960ii monitoring and control systems have:

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By default, the terminator on the board of VT336 and VT336PoE is always ON. The cap is inserted between the two contacts providing 120R resistance. The terminator is a J16 connector on the board.

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Connecting Modbus RTU sensors:

Example 1: Daisy chain connection (the main controller is located at the beginning of the chain)

  • Sensors are connected in a daisy chain connection.

  • 120Ω resistor is used at the end of the chain which is equal to the resistance of the cable.

  • A twisted pair cable is used for A(+) and B(-).

  • "VT336 and VT336PoE / DIN monitoring units" have an internal termination and by default, it is switched to ON position.

  • Up to 32 devices can be used.

  • Overall cable length is no more than 1000 meters.

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Example 2: (Not recommended) Daisy chain connection (the main controller is located in the middle of the chain)

"VT336 and VT336PoE / DIN monitoring units" have an internal termination and by default, it is switched ON.

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  • Sensors are connected in a daisy chain connection.

  • 120Ω resistor is used at the ends of the chain which is equal to the resistance of the cable.

  • A twisted pair cable is used for A(+) and B(-).

  • Up to 32 devices can be used.

  • Overall cable length is no more than 1000 meters.

...

Activation and Configuration of Modbus interface:

After all Modbus devices have been connected to it, you need to activate it and configure: Creating virtual Modbus RTU element

Accessories:

You can use a range of Sensors/Meters/Devices for Modbus.