Data acquisition circuit

The utility model relates to a digital acquisition circuit, which is characterized in that an external reference voltage is amplified by an operational amplifier and buffered by a reference voltage buffer and then is provided for an input end of a reference voltage source, namely, the reference voltage is provided for a data acquisition circuit; the eight-channel multiplexer receives input of eight external analog signals, and one of the received analog signals is selected through a control pin of the multiplexer and input to the programmable gain instrumentation amplifier for gain processing. The programmable gain instrumentation amplifier performs gain processing on the selected analog signal according to a signal gain requirement and then transmits the processed analog signal to the successive approximation type analog-to-digital converter; and the successive approximation analog-to-digital converter performs analog-to-digital conversion on the analog signal after gain processing, that is, the analog signa