摘要 |
A sonde includes a plurality of discrete sensing electrodes (34, 36) of analog output projecting from a housing within which are accommodated a microprocessor (16) and an A/D converter (40) to digitise the output of the electrodes (34, 36). A stirrer (136) is fully integrated into the housing and projects from the housing centrally with the electrodes around it. The stirrer motor (60) and the stirrer control (56) are integrated into the housing. The microprocessor (16) controls the stirrer control (56) e.g. as to on-off times, voltage and r.p.m. The sonde also has a readily attachable and detachable calibration cup (186) with wells (190) to enable each well to receive its own calibration solution and for all the electrodes to be calibrated simultaneously. <IMAGE> <IMAGE> |