Resistive Sensors Network Analog Multiplexing

This article is focused on developing a multiplexing system used to select and measure the transducers with the inner sensing element based on passive components. Those transducers are used on a very large scale in the hydrotechnical constructions automated monitoring procedure and the main category is represented by the three or four wire resistive transducers. The proposed solution aims to replace the old multiplexing systems based on electromagnetic relays which is strongly affected by the dam's inner environment conditions: excessive humidity, corrosion, etc. Due to those conditions, the relays are subject of premature wear and that leads to an irreversible contact oxidation which is very difficult to be kept under control. From the measurements point of view, the contact oxidation occurrence means “dead times” in the measurement series and the analyses of the dam behavior can be faulty. The alternative solution proposed in this article is based on using analogue switches [5]. From the command point of view the proposed analogue switch is compatible with an electromagnetic relay, from measurement point of view even with analogue switch may be obtained a low R
_ON
resistance around 0.6 Ω and resistance match between channels below 0.07 Ω.