Hach-Lange SURFACE SCATTER 7 sc Turbidimeter - Manual (Page 37)

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Operation
6. Open the SS7 sc to remove the plate. Restart the sample flow
and close the door. Confirm to return the instrument to
measurement mode.
Note: After confirmation of return to measurement mode, the instrument
will equilibrate for 2 minutes before the output mode changes. Instrument
measurements will show on the display, but the value will flash and a “OUT
MODE WARN” warning will display until the 2-minute equilibration period
is complete.
5.5.4 Instrument verification
Instrument verification is intended as a simple check to ensure
SS7 sc functionality between calibrations. Verifications should be
performed on a monthly basis using a manufacturer-provided
standardization plate.
A verification directly after calibration is used to establish the
baseline. Any verification afterwards, until the next calibration, that
uses the same verification standard will reference the recorded
value from the baseline verification as the “expected” value. In
order for the verification to pass, the measured value should be
within the limits set by the Pass/Fail Criteria of the baseline value.
Before starting the verification, read section 5.5.3 .
1. From the Main Menu, select SENSOR SETUP and confirm.
2. If multiple sensors are attached to the controller, choose
SELECT SENSOR>SS7 SETUP and confirm.
3. Select CALIBRATE and confirm.
4. Select VERIFICATION and confirm.
5. Select PERFORM VER and confirm.
6. The serial number on the standardization plate to be used for
verification should match the serial number listed on the VALID
SN screen. Confirm to accept the displayed serial number.
Important Note: If the serial numbers do not match, a verification
baseline (
section 5.5.3 ) must be established before verification can
be performed.
7. Select the available Output Mode (Active, Hold or Transfer)
from the list box and confirm.
8. Position the plate on top of the sample cylinder:
a. Shut down the sample flow and wipe off the top of the
sample cylinder.
b. Place the standardization plate on top of the sample
cylinder so that the light beam strikes the center of the
plate. Note the orientation of the plate and always place it
in the same position when using it to check standardization.
c. Close the door to eliminate stray light. Confirm to continue.