Abstract
A new method of multi-channel measurement of salt concentration is proposed on the basis of a microcomputer control technique for separation of electric resistivities on platinum probes which sense electrolytes.
Using analog multiplexers, square-wave current is supplied to each of the probes in due order. The signal detected synchronously is amplified, peak-held, digitalized and stored on the 256-Kbyte RAM which is the outer memory of the microcomputer. The control program codes by machine language.
This system has six following performance features : 32 channels, high-speed sampling of 100 μsec/channel (max.), response time of 50 psec, stability of ±0.15 %, accuracy of ±0.5% and wide range of salt concentration (50-1200 mg/l or 200-3500 mg/l NaCl).
The outline of the data processing program codes by BASIC language and some useful graphs such as deviation graph of NaCl tracer and contour map of salt concentration can be obtained.
