Content Comparison

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Function and purpose

It is an extension PCB board and should be purchased separately.

Allows to monitor up to 32 Modbus RTU devices/meters/sensors. The maximum distance of a daisy chain is up to 1000 meters. Each metered value of a Modbus device is addressed individually using input registers and is shown by the system as virtual sensors. You can configure thresholds and icon representations for these elements.

It can be used with VT335t, VT336t, VT825t, and VT855t monitoring systems. A slot PCB board can be inserted inside the monitoring unit while the unit is in operation. Has an internal termination and by default, it is switched ON (if required can be turned off).

Models

Picture	Extension	Used for monitoring systems
Image Added	VT485m	VT335t, VT825t, and VT855t
Image Added	VT485d	VT336t

Use cases

The Modbus RTU monitoring extension has various use cases across multiple industries and applications:

1. Industrial Automation: The extension can be used to monitor various industrial devices and meters, such as temperature sensors, flow meters, or energy meters. It allows for precise real-time monitoring and control of processes.

2. Building Management Systems (BMS): In a BMS setup, the extension helps monitor HVAC systems, lighting, and energy consumption using Modbus-compatible devices, ensuring efficient energy management and operation.

3. Data Centers: This extension can track critical environmental data such as temperature, humidity, or power usage across multiple Modbus-enabled devices within a data center, ensuring optimized conditions and early alerting in case of abnormalities.

4. Energy Management: For monitoring solar inverters, battery management systems, or other power meters, this extension facilitates efficient data acquisition and allows operators to maintain optimal energy flow and usage levels.

5. Remote Monitoring of Critical Infrastructure: The extension is useful in applications where remote sensors are deployed, such as in oil and gas pipelines, utility substations, or other infrastructure that requires remote monitoring and control.

These use cases make the extension crucial for maintaining operational efficiency, enabling preventive maintenance, and ensuring safety across industries.

Technical specification

Physical description

By default, the terminator on the board of VT335t, VT825t, and VT855t is always ON.

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b) "B-, A+, GND" - port for connecting Modbus RTU devices.

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(-).

• "VT335t, VT825t, and VT855t monitoring units" have an internal termination, and by default, it is switched to the ON position. (If it is required, it is possible to switch it OFF)

• Up to 32 devices can be used.

• Overall cable length is no more than 1000 meters.

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	VT485r	Cables	Eastron SDM220-MODBUS
	B-	red	+12V
	A+	blue	A+
	GND	white	GND

Physical description

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

"VT335t, VT825t, and VT855t 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.

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Activation and Configuration of Modbus interface

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

Include Page
Creating virtual Modbus RTU element Creating virtual Modbus RTU element

Accessories

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Some recommended readers Modbus configurations for tested sensors tested by Vutlan

Testing VT485m PCB using two Vutlan controllers

This section is useful for installers.

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