Industrial Sensors: The ‘All-Seeing Eye’ of On-Site Data Collection

In modern industrial automation systems, sensors play a crucial role, acting like the sharpest “all-seeing eye” on the production line. They are responsible for capturing key data about equipment operating status, environmental parameters, and production processes, transforming invisible industrial information into digital signals that can be processed by PLC systems.

The core function of sensors is signal conversion. They act like a precise “translator”, accurately converting various physical quantities (such as temperature, pressure, displacement) into standard electrical signals. This process is very similar to translating complex industrial language into simple instructions that computers can understand.

For example: a temperature sensor works like an accurate “temperature translator”. When the on-site temperature rises, the current or voltage output from the sensor also increases, allowing the PLC to accurately determine the specific temperature value.

Proximity Switches: The Non-Contact “Detectives”

Proximity switches are one of the most common sensors in industrial sites. They can detect objects without direct contact, like an invisible “detective”. The main working principles include:

• Inductive: Detecting metallic objects

• Capacitive: Detecting both metallic and non-metallic objects

• Photoelectric: Utilizing the photoelectric effect for detection

Typical Application Scenarios:

• Part positioning on precision assembly lines

• Counting materials on conveyor belts

• Stroke limit protection for machinery

Pressure Sensors: The Precise “Pressure Doctors”

Pressure sensors act like extremely precise “pressure doctors”, capable of accurately converting pressure levels into standard electrical signals. They play an important role in real-time monitoring and protection in various hydraulic and pneumatic systems.

Key Performance Indicators:

• Measurement range (0-10MPa, 0-20MPa, etc.)

• Measurement accuracy (usually ±0.5%~±1%)

• Response speed (milliseconds)

Temperature Sensors: The Precise Measurement “Temperature Stewards”

Temperature sensors come in various types:

• Thermocouples: Suitable for high-temperature measurement

• Thermistors: Suitable for medium and low-temperature measurement

• RTDs: High measurement accuracy

The output signals from sensors need to be processed by a converter (A/D converter) to be recognized and processed by the PLC. This process is like translating foreign languages into the “native language” that computers can understand.

Key Points of Signal Conversion

1. Analog signal conversion: Common standards include 4-20mA, 0-10V, etc.

2. Digital signal processing: Through the PLC’s analog input module

3. Signal filtering: Eliminating electromagnetic interference

Precautions

1. When selecting sensors, consider comprehensively:

* Measurement range
* Environmental adaptability
* Installation conditions

1. Pay attention to signal wiring to avoid electrical interference

2. Regular calibration to ensure measurement accuracy

When using sensors, be sure to:

• Strictly follow equipment safety operating regulations

• Wear necessary protective gear

• Regularly check the mechanical and electrical connections of sensors

• Keep sensors clean to avoid measurement errors

Sensors are like the most sensitive “tentacles” in industrial sites, silently collecting data to provide precise and reliable information support for production processes. Choosing the right sensor is like equipping the PLC system with the most sensitive “all-seeing eye”.