The M101E is equipped with an internally mounted low temperature converter which converts H2S at a closely controlled temperature setting of 315 °C, leaving other gases unaffected. The M102E uses a high temperature converter, mounted externally to the analyzer, and operates at a temperature of 850°C. TRS components (typically, H2S, methyl mercaptan, dimethyldisulfide and methyl-disulfide) are all converted to SO2 at this temperature, with efficiency greater than 98%.
Sample gas drawn into the analyzer first passes through a scrubber which removes all traces of sulfur dioxide. The converter then converts the components of interest to SO2. The resulting concentration for SO2 is then measured by fluorescence. In the basic configuration, the analyzer may be programmed to read H2S concentration (101E) or TRS (102E) only. However, a switching option, showing H2S/TRS and SO2 readings alternately, is available. Cycle times may be adjusted, and each reading is truly independent, having its own calibration slope and offset. A sample and hold circuit provides continual analog outputs for each channel. Calibration is simplified by the optional zero and span valves, which allow direct entry of calibration gases, or the optional permeation tube may be used to provide span checks. The analyzers feature auto zero which provides excellent zero stability.