YSI 600DW-B Sonde - Manual (Page 74)

Sondes Section 2
In most cases, the free chlorine sensor should be calibrated AFTER a logging study has been underway for
2-3 hours to assure the stabilization of the free chlorine sensor in the flowing tap water. The setup of the
logging study (or Unattended Sampling) is described in detail in
Section 2.7 UNATTENDED
SAMPLING and 2.9.1 Run UNATTENDED SAMPLING. To view the logged data to assure stability
prior to calibration, see
Section 2.9.3 File.
To calibrate the free chlorine sensor carry out the following steps:
Following the calibration of all other sensors present, reinstall the free chlorine probe in the sonde bulkhead
after removing the port plug. Make certain that no moisture is present in the port before installing the
probe and, if moisture is present from the previous calibration procedures, use compressed air to dry the
port.
• Break in the sensor according to the instructions in Section 2.6 above.
• Locate the flow cell which was supplied with your 6920DW or 600DW-B and attach it to the sonde
according to the instructions that were supplied with the flow cell. Note that for flow cell studies on
drinking water with the 600DW-B, YSI recommends that users purchase a 655488 Extended
Calibration Cup Sleeve and substitute the extended length sleeve from the calibration cup for the
shorter sleeve in the flow cell kit. The extra length will eliminate any bottom interference on the
turbidity readings and will be compatible with calibration of the turbidity sensor using the extended
length calibration cup.
• Attach inlet and outlet hoses to the barbed fittings supplied with the flow cell and then insert the
fittings into the proper ports of the flow cell. Make certain that the hoses are attached very snugly to
the barb fittings to prevent any possibility of catastrophic leakage. If necessary, standard hose clamps
can be used to secure the hoses to the barbed fittings.
• Connect the inlet line of the flow cell to a drinking water tap and run the outlet line to a drain.
Make certain that the inlet line is securely attached to the tap and that the outline line will not pop
out of the drain under flow conditions.
• Turn on the water to the cell so that the flow is 500-1000 mL per minute (minimum 500 mL/min)
and allow water to flow through the cell for at least 1 hour before proceeding.
• Set up your Unattended Sampling study as described above and allow readings to be logged to
internal memory for 2-3 hours. Using the File|View command as described in Section 2.9.3,
inspect the free chlorine readings and after they are stable proceed with the calibration as
described below.
• Collect a sample of water from the outlet hose of the flow cell and immediately analyze it for free
chlorine using an independent method, e.g., the DPD method with a YSI 9100 Photometer.
• Interface to the sonde using a 650 display/logger or a PC running EcoWatch for Windows.
Choose 8-Advanced and then 2-Setup and make certain that Autosleep RS-232 is active as
shown in the box below.
YSI Incorporated Drinking Water Monitoring Systems Operations Manual 2-67