Return code judging method and driving circuit of current type industrial control bus

Abstract

The invention discloses a return code judging method of a current type industrial control bus. The return code judging method comprises the steps of collecting detecting signals sent by a detector, transforming the detecting signals to amplified level signals, obtaining a basic level value, collecting a level value transformed by the collected detecting signals, calculating the difference between the transformed level value and the basic level value, and judging whether a return code exists according to the difference. The invention further discloses a driving circuit of the current type industrial control bus. Due to the fact that the basic level value and the level value after the detecting signals are transformed into the amplified level signal are obtained first, then the difference between the level value and the basic level value is calculated, the fact that whether a return code exists or not is judged according to the difference, and when a return code exists in the detecting signals, the difference is located within a fixed value range, and therefore according to the return code judging method, not only is the fact that whether a return code exists or not is easy to judge, but also the method is accurate and simple, and easy to realize.

Description

technical field [0001] The application relates to the field of fire alarm, in particular to a return code judgment method and a driving circuit of a current-type industrial control bus. Background technique [0002] At present, the existing return code judgment method of the current-type industrial control bus used for the circuit board of the fire alarm controller often adopts a fixed level comparison method to judge whether the detector has a return code. Since the signal amplifying circuit needs to filter out interference and current variation, it will inevitably cause changes in the return code waveform. Such as figure 1 As shown, the return code waveform (L - ) The levels at 1 and 2 are the same, but the waveform changes greatly after amplification, and the amplitude difference at points 1 and 2 is very obvious. Similarly, the amplitude of the amplified return code waveform also has a large change at different positions, as shown in the figure, there is a difference ...

AI Technical Summary

Problems solved by technology

like figure 1 As shown, the return code waveform (L - ) The levels at 1 and 2 are the same, but the waveform changes greatly after amplification, and the amplitude difference at points 1 and 2 is very obvious

Similarly, the amplitude of the amplified return code waveform also has a large change at different positions, as shown in the figure, there is a difference of 0.5V between the first and third wave amplitudes, which makes it difficult to distinguish the return code.

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