A measurement system for use with fluorescent chemosensors has multiple stimulus light sources each coupled to at least one sensor. Multiple sensors each receiving light from a different light source connect to each of one or more photodetectors. A processing device drives the light sources in a time-division multiplexed manner, and reads the photodetector at an appropriate time for each sensor. The processing device calibrates the sensor readings and provides them in a way that is identified to the associated sensor.