Technology

The Operation of Advanced Signal Isolators

The primary function of the signal isolators is to ensure reinforced isolation between the input and output. This is achieved by two identical insulation barriers within each Pinier product. The insulation barriers are constructed out of a thin layer of Silicon Dioxide (SiO2). As SiO2 has a very high dielectric strength (approx. 500 kV/mm) compared to other materials such as epoxy or even polyimide, it is very suitable as insulation barrier material. Besides, an additional layer of protection is added in case the primary insulation mechanism fails.

The input signals must cross the insulation barrier to reach the output of the signal isolator. To achieve this, the analog signals are modulated with a high-frequency carrier signal, allowing them to capacitively propagate through the insulation barrier. This method ensures exceptional resilience against common mode noise and transients (>85 kV/µs), which is essential for protecting low voltage signal and data processing equipment against electromagnetic interference (EMI). Gain and offset errors are kept to a minimum in this way.

The design architecture of Pinier's signal isolators is such that external power is only required on the secondary side. The supply for the primary side is generated within the isolator itself. This power conversion is performed by a high-frequency, inductor-coupled transformer. Like the signal path, the power path is also insulated for high voltage, while maintaining low input-to-output coupling capacitance to reduce EMI susceptibility of the secondary side equipment.

All Pinier's signal isolators include a diagnostic feature designed to detect failures within the application they are used, preventing hidden failures. For the 4-20mA output, this means the output loop current will be set to 2mA, indicating that power is present on the secondary side, but the output signal is not valid.

The products of Pinier are designed for a long lifetime. To ensure this, all high voltage isolators are potted in silicone. This process provides robust protection against moisture and debris, safeguarding the integrity of the insulation properties. Additionally, potting enhances resistance to mechanical shocks and vibrations, increasing durability and reliability. Furthermore, it offers excellent electrical insulation and effective thermal management, ensuring optimal performance under various conditions. The tamper-resistant nature of potting also ensures that the components remain secure and intact throughout their use.