Three Sensor Data Output Types

Sensors can provide measurement data through digital, analog, or switch outputs. The appropriate output type depends on factors such as transmission distance, electromagnetic interference, terrain, control-system compatibility, and whether continuous measurement data or threshold-based signals are required.

1. Digital Output

Digital-output sensors are available with RS232, RS485, or wireless transmission. Selection should be based primarily on the required transmission distance, the level of electromagnetic interference, and the complexity of the installation environment.

2. Analog Output

Analog-output sensors provide either a 4–20 mA current signal or a 0–10 V voltage signal. The output changes continuously with the measured distance, and each current or voltage value corresponds to a specific distance value within the configured measurement range.

4–20 mA Output Example

For example, the JGS-30A distance sensor has a measurement range of 0.2–30 m. Under its default current-output configuration:

• 4 mA corresponds to 0.2 m (200 mm).
• 20 mA corresponds to 30 m (30,000 mm).

The relationship between output current I and measured distance L is:

L = (I − 4) / Δi + 200

Where:

Δi = (20 − 4) mA / (30,000 − 200) mm

The analog output endpoints can be configured in either of the following ways:

1. Factory preset: The manufacturer sets the distance values corresponding to the minimum and maximum analog outputs according to the user’s requirements. In this configuration, users cannot modify the values themselves.
2. User-configurable: The configuration interface is made available so that users can set the corresponding distance values with dedicated setting software.

This applies to endpoint settings such as the distance represented by 4 mA and 20 mA, or by the minimum and maximum values of a voltage-output range.

3. Switch Output

Switch-output sensors support up to two sets of relay outputs. Each relay can correspond to a preset distance threshold. When the measured distance reaches the configured value, the corresponding output terminal disconnects.

As with analog-output settings, relay thresholds can be preset by the manufacturer according to the user’s requirements. If the configuration interface is left open, users can modify the thresholds using specialized setting software.

Output Type Selection Summary

• Select RS232 for short-distance digital communication within 10 m where electromagnetic interference is limited.
• Select RS485 for longer transmission distances, typically up to 1,000 m, or where stronger interference resistance is required.
• Select wireless transmission for complex terrain or installations where wiring is impractical.
• Select a 4–20 mA or 0–10 V analog output when continuous distance values must be transmitted to a compatible control or monitoring system.
• Select a relay switch output when the application only needs to respond after the measured distance reaches one or two preset thresholds.