the dark, the stock suspension stays stable for a maximum of one
year.
8. Prepare 20 NTU or 40 NTU standard suspension.
a. 20 NTU standard suspension: Dilute 10 mL of 4000 NTU stock
suspension to 2000 mL with filtered water. Gently swirl to mix.
b. 40 NTU standard suspension: Dilute 20 mL of 4000 NTU stock
suspension to 2000 mL with filtered water. Gently swirl to mix.
Clean and fill the flow chamber
1. Clean the flow chamber. Refer to Clean the flow chamber
on page 23.
2. Push MENU and select CALIBRATE>SENSOR>PRIMARY CAL
(primary calibration) or SAMPLE CAL (sample calibration).
3. Select an option.
Option Description
HOLD OUTPUTS Hold the analog outputs and relays at their present
values/on-off states.
XFER OUTPUTS Transfer the analog outputs and relays to set
values/states. Refer to SET TRANSFER setting in
Configure the analog outputs on page 19 and Configure
the relays on page 19.
ACTIVE
OUTPUTS
Let the analog outputs and relays represent the
measured turbidity.
4. Push ENTER to confirm.
5. Pour the sample of known value or prepared standard suspension
(20 NTU or 40 NTU) into the calibration funnel until the suspension
can be seen in the clear sight tube.
6. Hold the calibration funnel below the sensor height to drain the
sensor.
7. Do step 5 and 6 again to rinse the internal tubing of the sensor.
8. Pour the sample of known value or prepared standard suspension
(20 NTU or 40 NTU) into the calibration funnel until the flow chamber
is full.
9. Put the calibration funnel in the funnel holder.
Enter the value of the sample or standard suspension
1. From the “PRIMARY (or SAMPLE) CAL, SAMPLE READY?” screen,
push ENTER.
2. Let the reading stabilize which can take as much as 15 minutes, then
push ENTER.
Note: If the reading is not stable, "PLEASE WAIT" shows.
3. When "PRIMARY (or SAMPLE) CAL?" shows, enter the known value
of the sample or the standard suspension used. Push ENTER to
confirm. "PRIMARY (or SAMPLE) CAL: CONFIRM CAL OK?" shows
when the calibration is complete.
Note: If “CONFIRM FAILURE” shows, the calibration was not successful. Push
ENTER, then select CAL: EXIT to cancel the calibration or CAL: REPEAT to do
the calibration again.
4. Push ENTER to save the calibration. "Confirm Active?" shows.
Note: Push ESC to not save the calibration.
Return to operation
1. Remove the calibration funnel from the holder and hold it below the
sensor height to drain the sensor. Discard the used calibration
solution in accordance with local, state and federal disposal
regulations.
2. When the sensor is drained, put the calibration funnel in the funnel
holder.
3. Start the flow of sample through the flow chamber. Refer to Start the
flow on page 18.
4. Push ENTER. "CONFIRM ACTIVE?" shows.
5. When the reading that shows corresponds to the actual typical
process value, push ENTER to release the analog outputs and relays
to active outputs.
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