RS485, CAN or 4-20 mA: How to Choose an Inclinometer Output

An inclinometer can measure the correct angle and still fail as part of a system if its output interface is unsuitable. RS485, CAN bus and 4-20 mA are all widely used in industrial tilt measurement, but they solve different integration problems. The best choice depends on the controller, cable length, electrical environment, network structure and required data.

RS485: Flexible Digital Communication

RS485 is a differential digital interface designed for reliable communication over relatively long cables. It is widely supported by PLCs, industrial computers, gateways and data-acquisition equipment. Many industrial sensors use Modbus RTU over RS485, allowing the controller to request angle, temperature, status and configuration data.

RS485 is a strong choice for fixed equipment, structural monitoring, factory automation and systems containing several sensors on one bus. It offers more information than an analog signal and can reduce wiring when multiple devices share the same network.

Successful integration requires correct device addresses, baud rate, data format, cable type, grounding and termination. RS485 describes the electrical layer; the buyer should also confirm the communication protocol.

CAN Bus: Designed for Distributed Machinery

CAN is a robust multi-node communication system developed for environments where many controllers and sensors exchange data. It includes message arbitration and error detection, making it well suited to vehicles, construction machinery, mobile equipment, railway systems and other distributed control networks.

CAN2.0 and CANopen are not the same thing. CAN2.0 defines the communication technology and frame structure, while CANopen adds a standardized higher-level protocol. Confirm which version the existing controller supports before ordering the sensor.

CAN is often preferred when the inclinometer must join an existing machine network and provide rapid, repeated updates. Network bitrate, cable length, termination and message identifiers must be planned as part of the system design.

4-20 mA: Simple and Reliable Analog Transmission

A 4-20 mA output represents the measured angle as a current. Four milliamps normally corresponds to the lower end of the configured range and 20 milliamps to the upper end. Because the information is carried as current, the signal is relatively resistant to voltage loss over long cables and is familiar to process-control engineers.

This output is useful when an existing PLC has analog input modules or when the project needs a straightforward signal without digital protocol configuration. A current below the normal measurement range may also be used by some systems to identify wiring or sensor faults, although the exact behavior must be confirmed for the selected product.

The limitation is that one analog channel normally carries one measurement value. A dual-axis inclinometer may require two channels, and additional information such as temperature, diagnostics or configuration is not as convenient as with a digital interface.

What About 0-5 V Output?

Voltage output is simple and useful over short distances, especially for local control and test equipment. However, voltage signals are more sensitive to cable resistance, ground potential differences and electrical noise than a current loop. For long cables or demanding industrial environments, RS485, CAN or 4-20 mA is usually more practical.

Selection by Application

For machine leveling connected to an industrial computer, RS485 Modbus is often a convenient choice. For a crane, vehicle or mobile machine that already uses a CAN network, CAN2.0 or CANopen usually integrates more naturally. For a remote fixed sensor connected to a traditional PLC analog card, 4-20 mA may provide the simplest commissioning process.

If a project requires both a fast digital output and an analog signal, check whether the sensor supports combined interfaces. The Vigor SST810, for example, can be configured with RS485 Modbus plus 4-20 mA for dynamic applications.

Questions to Ask Before Ordering

Which interfaces are available on the controller? What protocol and data format does it support? How long is the cable? How much electrical noise is expected? Will several sensors share one bus? How many axes must be transmitted? Are temperature, diagnostics or raw motion data required? What update rate does the control loop need?

Also verify the sensor power supply, connector, pin definition, grounding method and termination requirements. Interface names alone are not enough to guarantee compatibility.

Vigor Interface Options

Vigor inclinometer families support several integration methods depending on model and configuration. SST100, SST300 and SST400 are available with common industrial digital or analog outputs for static measurement. SST400 supports RS232 as standard with optional RS422, RS485, CAN2.0, CANopen, Ethernet, 0-5 V and 4-20 mA configurations. SST810 supports RS485 Modbus, CAN2.0, CANopen and RS485 plus 4-20 mA for dynamic motion applications.

Conclusion

Choose RS485 when you need flexible digital communication and multi-sensor networking. Choose CAN when the inclinometer must operate inside a vehicle or machine control network. Choose 4-20 mA when simplicity, long-distance analog transmission and PLC compatibility are the main priorities. The correct interface is the one that matches the complete control architecture, not simply the one with the most features.