YOKOGAWA TB820D, User Manual, Page: 56 / 87

< 7. Calibration >
7-7
IM 12E01B30-02EN 2nd Edition : June 09 , 2021-00
7.3 Zero Calibration
Supply Zero water or turn off the light source to perform Zero calibration. See ■ Zero standard
(7.2) to confirm about zero water.
[How to perform Zero calibration]
1 Turn on the maintenance mode.
2 Clean the Flow cell.
3 Prepare to supply Zero water.
<Manual supply of Zero water>

Remove the top cover at the top of the detector.

Loosen the four screws fixing the clear cover and remove the clear cover.

Use a funnel and pour zero turbidity water down the side of the funnel into the Flow cell.
Fill the cell with the water to a little higher level than the measurement window.

When the Flow cell is filled up to the level, drain the water which has been poured.

Pour slowly zero water down the side of the funnel again. Do not allow bubbles enter
the cell.

When the Flow cell is filled with the zero water for the second time to the level which is a
little higher than that of the measurement window, put the top cover in place.
<Using filtered water>

Open the valve for zero water and run a filtered water as zero reference.
<Zero by light source off>
Selectable when the measured turbidity is 40 NTU or above.

Turn LED OFF from Maintenance Menu.
3 Press on Main screen and go to the calibration menu.
4 On the calibration menu, select Zero calibration.
5 Confirm the reading is stable. Press [check stability].
6 After the message pops saying the reading is stable, confirm that the calibration value is
zero. Then press [Next].
7 Check the result of calibration and press [Accept] to update the Zero of the calibration
parameter.
8 If Light source has been turned off, turn on the light source.
To shift to the slope calibration, proceed to the steps of 7.4 of 7.5. If you finish the operation,
fix the clear cover and feed the sample with the top cover on. Turn off the maintenance
mode to end the calibration.