SEISAR-5 Portable Seismic Recorder with Low Energy Consumption for Autonomous Operation in Harsh Climatic Conditions

Abstract

An autonomous three-channel digital recorder developed at the Schmidt Institute of Physics of the Earth, of Russian Academy of Sciences is considered. The recorder was designed to meet the requirements of particularly difficult climatic conditions, minimum energy consumption, and ease of maintenance. Special attention is devoted to the reliability of data storage in case of sudden power loss, for which a new file-free recording format was developed. For each second of data recording, the system assigns a service line consisting of the exact time, the station code, and the station’s coordinates. This prevents loss of data when reading. When power is restored, the recorder automatically switches to the operating mode and continues the interrupted recording. The power supply for the analog part of the recorder is galvanically decoupled from the power supply of the digital part and carefully smoothed by special linear stabilizers and filters. To exclude the penetration of pulsations from the digital to the analog part by the common (grounded) wire, the control interface of the ADC is separated from the microcontroller by digital galvanic isolation circuits. Recorded data is recovered from the instrument by replacing the memory card, which takes just a few seconds. The control functions are also minimized, since the recorder has only two control buttons. The ease of maintenance allows quick installation of a large number of seismic stations with a small number of staff. The most important feature of the recorder is significantly reduced power consumption (less than 0.7 A h per day at a supply voltage of 12 V). This is five to six times lower than that of domestic and foreign counterparts and allows the recorder to operate on a single set of dry manganese–air batteries with a capacity of 150 A h and a weight of 4 kg for more than 6 months. As a component of seismic monitoring systems and in conducting epicentral measurements, these recorders are used in all climate zones of the Northern Hemisphere, from Serbia to Sakhalin and from Yakutia to Bangladesh; they have proved reliable and low-maintenance devices.