MIRAN Displacement sensors have various output signal types, with the mainstream ones including voltage signals, current signals, digital signals, etc. Among them, the voltage output type and current output type solutions are mature, with friendly production and back-end acquisition costs, and are the most widely used in the field of industrial automation.

The internal resistance of the voltage output signal is relatively high, and the working current of the circuit is relatively small. The signal acquisition can be completed by matching a high input impedance operational amplifier at the back end. The overall circuit power consumption is low, and the wiring and debugging are simple. However, due to the influence of output characteristics, voltage signals are more prone to coupling with external noise. When wiring over long distances, signal attenuation is more likely to occur, and the hysteresis and waveform distortion caused by cables are more obvious. It is more suitable for internal measurement and control scenarios of equipment with clean working conditions and short transmission distances.

The internal resistance of the current output signal is too low to be directly read. A load resistor needs to be connected in series at the receiving end, and the signal analysis is achieved by collecting the voltage across the resistor. Compared with voltage signals, current signals have outstanding anti-interference capabilities, and are less likely to experience signal attenuation and hysteresis distortion during transmission, making them suitable for complex wiring scenarios. To ensure the stable operation of the sensor output circuit, the current output scheme has an upper limit on the load resistance, and the power consumption of the loop is relatively higher. The current output form generally adopts independent loop wiring. When multi-channel synchronous measurement and control is carried out, it can effectively reduce signal crosstalk between channels.

In terms of wiring methods, the current of the voltage signal loop is relatively small, and the common ground scheme is often adopted for multi-channel wiring. The current in the current signal loop is larger, and independent loop wiring is generally adopted. At the signal acquisition level, voltage signal detection is intuitive and convenient. The current signal must be converted from current to voltage with the aid of high-precision standard resistors before measurement.

In the field of industrial automation, both voltage and current signals are standard analog signals and are the mainstream data transmission methods in industrial control systems. When fieldbus technology emerged in the early days, many people believed that analog transmission would gradually be replaced. However, after long-term industry verification, analog sensing solutions have been continuously iterated and still have outstanding value in terms of equipment compatibility, implementation cost, and operational stability. They can be seamlessly integrated with various mainstream PLCS and motion controllers and are compatible with new and old equipment renovation projects. Voltage output and current output displacement sensors each have their own advantages and can be flexibly selected based on the on-site working conditions. To reduce the error of the entire displacement measurement and control system, the voltage signal acquisition circuit needs to increase the input impedance as much as possible, while the current signal acquisition circuit needs to reduce the input impedance. For a numerical control system, voltage, current and digital signals will eventually be converted into level signals for processing by the processor. Current signals also need to be matched with load resistors to be converted into voltage signals for processing. For working conditions with a high density of frequency converters, a lot of dust and oil stains, strong electromagnetic interference or long wiring distances, it is recommended to give priority to using current output type displacement sensors, which are suitable for harsh scenarios such as construction machinery, shield equipment, water conservancy gate monitoring, and outdoor structure monitoring.

In response to the upgrading trends of intelligent manufacturing and industrial Internet of Things, many displacement sensors support the optional or compatible output of analog and digital signals. They not only retain the advantages of analog signals, such as easy debugging and strong versatility, but also can be connected to edge acquisition terminals and Internet of Things monitoring platforms. At present, various displacement sensors, relying on mature and stable analog output solutions, are widely used in fields such as rubber and plastic machinery, hydraulic equipment, precision detection, bridge and tunnel monitoring, and new energy equipment, providing reliable position perception solutions for automatic control systems.