The MAX® 50 series analyzers (MAX® 50, MAX® 20, MAX® 10, and the LX-10 and the LX-50) use early 1980’s technology for heat control. These units use a soldered RTD and a “temperature offset” to compensate for the temperature difference measured between the RTD and the sample surface. This offset can be as much as 19°C depending upon the instrument’s test temperature, programming, and the sample size. The MAX®50 series units measure the resistance output from the temperature sensor based upon fixed milliampere input. Changes in resistance within the RTD circuit (such as corrosion), RTD position relative to the burner coil, electronic drift, and sample sediment on the sensor will all affect the sample’s perceived testing temperature.
The MAX® 50 series moisture analyzers use one of (or a combination of) three fixed ending criteria to predict the endpoint moisture value. The ending criteria designed for low moisture samples or for greatest accuracy is designated the “EC06” program. The EC06 program requires that the difference between predicted and actual moisture be less than 0.015%. It also requires successive predictions to agree within 0.0075%.
The most commonly used ending criteria in the MAX® series is the “EC97” program. This program requires that the difference between predicted and actual moisture levels be less than 0.2425%. It requires successive predictions to agree within 0.12%. The “EC255” program is designed for high moisture samples or for fastest test times. This program requires that the difference between predicted and actual moisture levels be less than 0.6375%. It requires successive predictions to agree within 0.32%.
In addition, the MAX® 50 series firmware “relaxes” or loosens the ending criteria as the moisture level in the sample increases. At higher moisture levels the criteria are increased by 0.01% for each 10% increase in moisture content. This enables shorter test times at higher moisture levels, without a loss in statistical precision.
Other specialized programs exist for the MAX® 50 series to accommodate specific testing needs and requirements. Contact Customer Service for specific information regarding these programs.