How does the FT660 or 1720E perform a Zero Electronics cycle?

Document ID

Document ID TE6101

Published Date

Published Date 13/03/2017
Question
How does the FT660 or 1720E perform a Zero Electronics cycle?
Summary
Summary of how the FT660 and 1720E completes an electronics zero or dark measurement.
Answer
With the instrument in-process (photocell submerged in the water), a zero electronics is automatically done around midnight by either instrument and the value is used for the next 24 hours, unless the operator chooses to run a  zero electronics at some other point during the day.

Once the light source is turned off (laser for FT660 and incandescent lamp for 1720E), a measurement is made. This measured value is subtracted from all subsequent measurement to calculate turbidity.

Note: in some literature, this process is also referred to as a "dark measurement".