Industrial automation demands reliable, accurate sensor integration, and NORVI controllers 4-20mA support delivers exactly that. These ESP32-based programmable controllers provide seamless connectivity with industrial sensors, offering engineers and automation professionals a cost-effective solution for real-time monitoring and control applications.
Understanding NORVI 4-20mA Controllers
NORVI controllers with built-in 4-20mA support are ESP32-based industrial PLCs designed specifically for harsh industrial environments. The 4-20mA current loop standard remains the backbone of industrial instrumentation because it offers exceptional noise immunity and can transmit signals over long distances without degradation.
Why Choose 4-20mA Analog Input Controllers?
The 4-20mA standard has dominated industrial automation for decades. Unlike voltage signals that suffer from voltage drops and electromagnetic interference, current loops maintain signal integrity across hundreds of meters of cable. NORVI industrial controllers leverage this proven technology while adding modern IoT capabilities through ESP32 integration.
Key Features of NORVI Industrial Controllers
Built-in Analog Input Support
NORVI PLC 4-20mA models incorporate high-precision 16-bit ADC (Analog-to-Digital Converters) using the ADS1115 chipset. This configuration provides exceptional accuracy for industrial sensor readings, whether you’re monitoring temperature, pressure, flow rate, or liquid level.
The analog input architecture uses I2C communication protocol, with each input independently addressable. This design allows up to four expansion modules, significantly increasing the analog input capacity of your automation system.
Comprehensive Hardware Specifications
Digital Capabilities:
- Multiple digital inputs with both sink and source configuration options
- Relay outputs rated at 5A for direct load control
- Transistor outputs for high-speed switching applications
Communication Interfaces:
- Built-in Ethernet (W5500) for industrial networking
- RS-485 Modbus support for legacy system integration
- WiFi and Bluetooth connectivity through ESP32
- GSM/LTE options for remote monitoring applications
Additional Features:
- Integrated OLED display (128×64 pixels) for local HMI
- DS3231 RTC with CR2032 backup battery for accurate timekeeping
- MicroSD card slot for data logging applications
- USB programming interface for easy development
Popular NORVI 4-20mA Controller Models
NORVI ENET-AE06-I
This flagship model combines Ethernet connectivity with six 4-20mA analog inputs. The ENET-AE06-I represents the perfect balance between functionality and affordability for medium-scale industrial automation projects. It includes all standard NORVI features: built-in display, RTC, SD card support, and comprehensive I/O options.
NORVI ENET
Digital Inputs | Relay output | 0 – 10V / / 4- 20 mA | Ethernet connectivity – W5500 | RTC with backup battery
NORVI-EX-ANI01 Expansion Module
For applications requiring additional analog inputs, the EX-ANI01 expansion module adds four 4-20mA inputs via I2C interface. The module features DIP switch address configuration, allowing up to four expansions to be daisy-chained to your primary controller. This modular approach provides scalability without requiring complete system redesigns.
Expansion Module
16-bit Analog Inputs (0–10V DC / 4–20mA models) | 12–24V Input Voltage | ADS1115 I2C ADC, Address Configurable | Optically Isolated Transistor Outputs (Loads up to 24V DC) | MCP23008 & MCP23017 I2C I/O Expanders, Address Configurable
Technical Implementation: Connecting 4-20mA Sensors
Signal Conditioning and Conversion
NORVI ESP32 controllers handle 4-20mA signal conversion through precision current-to-voltage conversion circuits. The process involves a shunt resistor that converts the sensor’s current output into a measurable voltage within the ADC’s acceptable range.
The INA196 amplifier measures voltage drop across the shunt resistor. Using Ohm’s law (V = I × R), a 10-ohm shunt resistor converts the 4-20mA range to 40-200mV. The INA196’s 20 V/V gain amplifies this to 0.8-4.0V, perfectly matching the ADS1115 input specifications.
Wiring Configuration
Industrial 4-20mA sensors typically operate on loop power, where signal and power share the same two-wire connection. NORVI controllers provide proper terminals for both powered and non-powered sensor configurations, with clear polarity markings to prevent installation errors.
Programming Your Analog Inputs
Programming NORVI controllers follows familiar Arduino IDE conventions. The Adafruit_ADS1X15 library provides straightforward analog reading functions. After initializing I2C communication on the correct GPIO pins (typically GPIO16 for SDA and GPIO17 for SCL), reading analog values requires only a single function call.
Advantages of ESP32-Based Industrial Controllers
Cost-Effective Automation Solutions
Traditional industrial PLCs often carry premium price tags that challenge project budgets. NORVI controllers deliver industrial-grade reliability at a fraction of the cost, making automation accessible to smaller operations and pilot projects.
IoT Integration Made Simple
The ESP32 platform brings native WiFi and Bluetooth capabilities to industrial automation. This connectivity enables remote monitoring, cloud data logging, and integration with modern IIoT platforms without additional communication modules.
Flexible Programming Environment
NORVI supports multiple programming environments including Arduino IDE, ESP-IDF, and industrial protocols like Modbus. This flexibility allows developers to choose their preferred tools while maintaining compatibility with existing industrial systems.
Real-World Applications
Process Monitoring and Control
Manufacturing facilities use NORVI 4-20mA controllers to monitor critical process parameters. Temperature sensors in chemical reactors, pressure transmitters in pneumatic systems, and flow meters in distribution networks all connect seamlessly to NORVI analog inputs.
Environmental Monitoring Systems
Water treatment plants deploy NORVI controllers for pH monitoring, chlorine level detection, and flow rate measurement. The combination of 4-20mA accuracy and IoT connectivity enables both local control and remote oversight.
Building Automation
HVAC systems leverage NORVI’s analog capabilities for temperature control, airflow monitoring, and energy management. The built-in display provides local status indication while WiFi connectivity enables integration with building management systems.
Expansion Capabilities
Modular System Design
NORVI’s expansion module ecosystem allows systems to grow with your needs. The I2C-based expansion architecture supports mixing analog input modules (both 0-10V and 4-20mA variants), digital I/O expansions, and analog output modules within the same controller.
Analog Output Modules
While this guide focuses on 4-20mA inputs, NORVI also offers analog output expansion modules. These 4-channel boards provide 4-20mA, 0-20mA, or 0-10V outputs for controlling variable frequency drives, pneumatic valves, and other analog actuators.
Getting Started with NORVI Controllers
Hardware Setup
Setting up your NORVI controller begins with proper mounting on standard DIN rail. Power connections require 24VDC industrial power supplies. Sensor wiring follows standard industrial practices with attention to proper grounding and shielding.
Software Configuration
Arduino IDE setup requires adding the ESP32 board definitions and installing necessary libraries including Adafruit_ADS1X15 for analog reading, Adafruit_SSD1306 for display control, and RTClib for real-time clock functionality.
Calibration and Testing
Before deploying to production, calibrate analog inputs using precision current sources or known-good sensor outputs. NORVI’s 16-bit resolution provides ample accuracy for most industrial applications, but proper calibration ensures optimal performance.
Best Practices for Industrial Implementation
Noise Mitigation
Despite 4-20mA’s inherent noise immunity, proper installation practices remain important. Use shielded cables for sensor connections, maintain separation between power and signal wiring, and ensure solid grounding throughout your installation.
Power Supply Considerations
Stable 24VDC power is crucial for consistent analog readings. Industrial-grade power supplies with proper filtering prevent power-related measurement errors. Consider UPS backup for critical monitoring applications.
Documentation and Maintenance
Maintain thorough documentation of sensor assignments, I2C addresses, and calibration data. Regular maintenance should include checking terminal connections, verifying sensor operation, and updating firmware when improvements become available.
Comparison: NORVI vs Traditional PLCs
Traditional industrial PLCs excel in established facilities with large installed bases of similar equipment. However, NORVI controllers offer compelling advantages for modern applications:
- Connectivity: Native IoT capabilities without expensive communication modules.
- Programming: Familiar Arduino environment versus proprietary ladder logic.
- Cost: Significantly lower initial investment and expansion cost.
- Flexibility: Open-source ecosystem with extensive community support
Futureproofing Your Automation Investment
Industry 4.0 Readiness
NORVI controllers position your facility for Industry 4.0 initiatives. Built-in connectivity enables predictive maintenance through continuous monitoring, while data logging capabilities support process optimization efforts.
OPC UA and Modbus Support
Industrial communication protocols like Modbus RTU/TCP ensure NORVI controllers integrate with SCADA systems and existing automation infrastructure. This interoperability protects your investment while enabling gradual modernization.
Troubleshooting Common Issues
Analog Reading Instability
Unstable readings often result from inadequate power filtering or improper grounding. Verify power supply quality, check ground connections, and ensure proper cable shielding. Software averaging can help smooth minor fluctuations.
Communication Problems
I2C communication issues typically stem from incorrect GPIO assignment or address conflicts. Verify I2C initialization uses correct SDA and SCL pins, and confirm expansion module addresses don’t overlap.
Display or RTC Issues
Both the OLED display and RTC use I2C communication. If one functions while the other fails, check individual I2C addresses and ensure proper library initialization sequences in your code.
Conclusion
NORVI controllers 4-20mA bring industrial automation into the modern era without sacrificing the reliability and accuracy demanded by critical applications. By combining proven 4-20mA analog technology with ESP32’s powerful processing and connectivity, these controllers deliver exceptional value for automation projects of any scale.
Whether you’re retrofitting legacy equipment, building new monitoring systems, or exploring IIoT opportunities, NORVI industrial controllers provide the perfect platform. Their modular design, comprehensive I/O options, and accessible programming environment make professional-grade automation achievable for organizations of any size.
Ready to modernize your industrial automation? Explore the complete range of NORVI 4-20mA controllers and expansion modules at NORVI’s official store and join the growing community of engineers leveraging affordable, powerful ESP32-based industrial control solutions.
Related Resources:
- How to Connect 4-20mA Industrial Sensors with ESP32 PLC
- NORVI ENET-AE06-I User Guide
- Understanding PLC Expansion Modules
- NORVI Products Overview