32-recirculating loop analogue signal telemetering device

Abstract

The present invention relates to a telemetric device 32-circuit analog signal and comprises a power supply circuit (1), a signal acquisition circuit (2), a signal filtering circuit (3), a frequency sampling circuit (4), a second voltage reference circuit (5), a first voltage reference circuit (6), a 485 communications circuit (7) and a CPU (10). The CPU adopts the high-speed, 16-bit and single-chip DSPIC33FJxxxGPx10 with a DSP core which is produced by the American Microchip Corporation; the voltage output of the first voltage reference circuit is connected with the common end of input signals and provides the 32 circuit input signals with a DC offset voltage; the 32 circuit input signals are sampled and converted after respectively entering the signal acquisition circuit, and are then respectively connected with the 32-circuit analog input end of the CPU through the signal filtering circuit; the two serial communication openings of the CPU are respectively connected with a RS485 conversion chip through the transmitting optical coupler and the receiving optical coupler of the 485 communications circuit. The telemetric device can greatly simplify the circuit structure of the peripheral hardware of the CPU, reduce the cost of the system, and improve the reliability of the system.

Description

technical field [0001] The invention relates to a multi-channel analog signal telemetry device used in the fields of intelligent power distribution, industrial automation and the like. By connecting voltage or current transformers, transmitters and other components, it is used to collect analog signals such as current, voltage, power, temperature, humidity, pressure, flow, etc., which are converted into digital signals by this device and realized and monitored through communication connections. System data exchange, so as to realize the function of remote telemetry. It belongs to the technical field of power distribution intelligent components. Background technique [0002] At present, the existing single-channel or multi-channel analog signal acquisition devices generally use figure 1 and figure 2 These two implementations: [0003] Method 1: see figure 1 , using multiple analog switches to switch the input channel; using a full-wave rectifier circuit to convert the i...

AI Technical Summary

Problems solved by technology

[0006] Method 1: Complex circuit structure and inaccurate harmonic measurement

[0007] like figure 1 , use the rectification method to convert the AC signal into a DC signal and then perform analog-to-digital conversion processing. Generally, the input signal needs to be conditioned first, then half-wave or full-wave rectification is performed, and then connected to a low-pass filter circuit, while the low-pass filter It will cause the attenuation of the harmonic content in the signal, and after the signal is converted by AC-DC in this way, the analog-to-digital conversion chip in the subsequent stage cannot accurately measure the harmonic component in the input signal, resulting in measurement errors

[0008] Method 2: The input signal channel is limited and the circuit structure is complex

[0009] like figure 2 , the use of AC sampling can well avoid the problem of inaccurate harmonic measurement in the rectification method, but because of the real effective value calculation, the input signal needs to be discretely processed first, and the calculation time is long, while the true effective value calculation The amount of data is large, and too many input and acquisition channels will directly affect the response time of the system, so it is necessary to use a high-speed CPU or DSP to process

And if multi-channel signal collection is to be realized, multiple analog-to-digital conversion chips and analog switches must be used to switch signal channels in the hardware structure, which reduces system reliability and increases product cost and system complexity

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