Development of a Multi-Channel Array Resistivity Method Instrument System

Application scenarios and experimental methods in the field of modern electrical exploration are becoming increasingly complicated, expanding requirements on instrumentations. Currently, the commonly used resistivity method instrument systems are mostly single-channel transmitting and receiving, which lowers the measurement efficiency. The multichannel array resistivity method instrument system developed in this article adopted an improved automatic measurement method to realize array synchronous transmitting and receiving, which effectively improve the measurement efficiency. The instrument mainly consists of two parts: a transmitter and a receiver subsystem. The transmitter subsystem realizes array transmitting through centralized electrode units or serial electrode management nodes. The former can support up to 256 electrodes with a maximum transmit power of 600 W; the latter can support up to 65 535 electrodes with a maximum transmit power of 5 kW. The receiver subsystem consists of multiple eight-channel receivers. The root-mean-square (rms) noise of the receivers is lower than
$9.38 ~\mu \text{V}$
, the dynamic range is better than 120 dB, and the isolation between channels is better than 119 dB. Combined with a built-in 4G and Wi-Fi module, it can achieve real-time monitoring of data quality and cloud storage functions. The results of the water tank comparison experiment between the developed instrument and GRx8-32 showed well consistency. By applying the developed system to the monitoring of the perfusion process of structured cementitious materials, the relative changes in resistivity of the perfusion process can be visually monitored, which lays a foundation for the application of the instrument in 2-D and 3-D detection and time-shift monitoring in other fields.