Sondes
Section
2
YSI Incorporated
Drinking Water Monitoring Systems Operations Manual
2-37
NOTE: At the end of the break-in period, the Cl2 Charge value should have a value between zero (0)
and 35. If the Cl2 charge value is greater than 35, a new membrane should be installed and the
activation and break-in process should be repeated.
The free chlorine system should be calibrated using the same basic methods employed for other sonde
sensors. The important thing to remember is to calibrate your sensor versus a flow cell effluent in the
mode which you will be using to measure free chlorine. There are four basic modes of operation as
described below with their corresponding calibration instructions:
1.
Stand-alone applications where data is being logged only to the internal memory of the
sonde at a user selected interval.
For this mode of operation, make certain that the Autosleep
RS232 feature is activated in the
Advanced|Setup
menu and that the Chlorine warm-up time is set
to 60 seconds in the
Advanced|Sensor
menu. With these software entries in place, the user will
input the free chlorine value from the DPD analysis of the flow cell effluent, and the unit will
automatically calibrate after the selected warm up time. This method is described in greater detail
below.
2.
Applications where the sonde is attached to a YSI 6500 Process Monitor utilizing the Sample
and Hold feature of the sonde software.
For this mode of operation, first activate the
Sample
and Hold
feature from the
Setup sonde
menu of the 6500 (Press the
Esc
and
Enter
keys of the
6500 front panel simultaneously to access this menu). Then select the desired interval for data to
be sent to the 6500. Exit to the main display mode of the 6500 by pressing the
Esc
key
repetitively and then press the
Cal
key on the 6500 front panel. Highlight the free chlorine sensor
entry, enter the value from the DPD analysis of the effluent and press
Enter.
Then press
Enter
again to confirm the calibration. See Section 4 of the 6500 manual for detailed calibration
instructions.
3.
Applications where the sonde is attached to a YSI 6500 Process Monitor and is outputting
data continuously to the 6500.
For this mode of operation, access the
Sonde setup
menu of the
6500 as described above and make certain that the Sample and Hold feature is INACTIVE. Then
exit to the main display mode of the 6500 by pressing the
Esc
key repetitively and press the
Cal
key on the 6500 front panel. Highlight the free chlorine sensor entry, enter the value from the
DPD analysis of the effluent and press
Enter.
Observe the free chlorine readings in real-time
and, when stable, press the
Enter
key to confirm the calibration. See Section 4 of the 6500
manual for detailed calibration instructions. Note that this mode of operation is NOT
RECOMMENDED by YSI due to sensor maintenance issues which are explained in detail in
Appendix G of this manual.
4.
Applications where the sonde is attached to a PC and data is being displayed to the
computer monitor using the Real-Time mode of Ecowatch for Windows.
For this mode of
operation, your must calibrate the free chlorine sensor before activating the Real-Time EcoWatch
mode or after activating the Real-time feature of EcoWatch. Access the sonde menu after
connection of the sonde to a PC or 650 Display logger and make certain that the Autosleep RS232
feature is activated in the
Advanced|Setup
menu and that the Chlorine warm-up time is set to 60
seconds in the
Advanced|Sensor
menu. With these software entries in place, the user will input
the free chlorine value from the DPD analysis of the flow cell effluent, and the unit will
automatically calibrate after the selected warm up time. Following calibration, attach the sonde to
the PC and click on the Real-Time entry in the top toolbar (Do NOT click on the sonde icon in the
lower toolbar). The Real-Time study will start automatically with data displayed graphically on
the PC monitor and logged to the hard drive of the PC under the file name which you have
selected. See Section 4.3.5 of this manual for detailed instruction in using the EcoWatch Real-
Time mode.
Details of the calibration for the simple
Unattended sample
mode of operation (#1 above) are provided
below. The initial instructions involving the setup of the flow cell/sonde system are also valid for
calibration in the other modes of operation.
