Why you should simulate temperatures during the design verification process
Product development engineers working on embedded systems often need to test how their systems respond to various temperatures. If their system has inputs for temperature sensors, they must connect a sensor and verify that the system reacts correctly to the measured temperature. However, changing the actual temperature in a test bed can be challenging and time-consuming. A more efficient approach is to replace the physical sensor with a simulated one.
For resistive temperature sensors, such as Thermistors (NTC/PTC) or Resistance Temperature Detectors (RTDs), simulation can be achieved using a resistor. By adjusting the resistance value, different temperatures can be emulated. This can be done manually using a potentiometer or a decade resistor by calculating the resistance corresponding to a specific temperature.
To automate this process and enable dynamic temperature simulation over time, a programmable resistor can be used. A programmable resistor allows resistance values to be controlled by a computer-generated signal, automatically adjusting the resistance to match the required temperature. This approach is particularly useful in Hardware-in-the-Loop (HiL) testing, where real-time sensor simulation is essential for validating embedded system behavior under different temperature conditions.
Sensor Simulation and HiL Testing
Simulating a temperature sensor with a programmable resistor is highly beneficial in HiL testing environments. HiL testing is a technique where real hardware components interact with a simulated environment, enabling engineers to validate embedded systems in a controlled and repeatable manner. Instead of exposing a system to varying temperatures in a physical environment, a programmable resistor can simulate different sensor readings by dynamically changing its resistance. This method ensures consistent testing conditions, reduces testing time, and improves accuracy in evaluating system performance.
Using a programmable resistor, engineers can:
- Simulate temperature changes dynamically in software-driven tests.
- Automate resistance adjustments to match specific temperature profiles.
- Perform long-duration tests with precise control over simulated conditions.
- Validate system responses without requiring physical temperature variations.
WireFlow’s Programmable Resistor Solutions
WireFlow offers two programmable resistor modules designed for temperature sensor simulation:
WF 3144 – C-Series Programmable Resistor Module
The WF 3144 is a programmable resistor module designed for NI CompactRIO chassis. As a C-Series module, it integrates directly into CompactRIO systems, allowing seamless control through LabVIEW. This module is ideal for engineers already using CompactRIO in their test environment and looking for a robust solution for sensor simulation in automated testing setups.
WF 2144 – USB Programmable Resistor Module
The WF 2144 is a standalone USB-controlled programmable resistor. It connects directly to a computer via USB and features an open communication protocol, enabling integration with various programming languages, including LabVIEW and Python. This flexibility makes the WF 2144 a great option for engineers who need a simple yet powerful tool for sensor simulation.
Application Notes and Resources
WireFlow provides detailed application notes on how to simulate specific temperature sensors using LabVIEW:
- PT100 Simulation using a Programmable Resistor: Read more
- NTC Thermistor Simulation using a Programmable Resistor: Read more
Additionally, an application note is available that describes how the WireFlow WF3144 module was used in a HiL test for a vibratory roller: Read the application note
Conclusion – Use a programmable resistor for simulating different temperatures
Simulating temperature sensors using a programmable resistor is an efficient and reliable method for testing embedded systems. Whether for manual testing with a simple resistor or automated simulation with a programmable resistor, this approach offers precise control over test conditions. HiL testing environments benefit significantly from this method, enabling engineers to perform repeatable and automated tests without needing physical temperature variations.
WireFlow’s WF 3144 and WF 2144 programmable resistor modules provide versatile solutions for engineers seeking to simulate temperature sensors accurately. With application notes and example code available, integrating these tools into your test environment is straightforward and effective.
