YSI 600DW-B Sonde - Manual (Page 288)

Frequently Asked Questions About YSI Drinking Water Systems Appendix H
electrode (ISE) sensors, but their use is not recommended for long term monitoring in flow cell applications
due to the potential for large drift. In addition, the 6920DW can measure either Rhodamine WT or
chlorophyll INSTEAD OF turbidity, but these analytes are not expected to be important for most drinking
water applications. Potential users should note carefully that the DW sondes will NOT MEASURE
DISSOLVED OXYGEN as explained in the next section.
What are the differences between YSI DW instruments and YSI 6-series sondes which have been sold
for surface- and ground-water applications over the last 13 years?
Other than the sonde overlay which indicates the sonde is a “DW” (600DW-B or 6920DW) version, the
appearance and mechanical design of the two drinking water instruments is identical to their surface-and
ground-water equivalents (600XLM and 6920). However, the most critical unique feature of the DW
sondes is the fact that they contain a different internal PC board which supports the free chlorine sensor, but
not a dissolved oxygen sensor. Because of this new hardware which reflects the different polarizing
potentials necessary for oxygen and chlorine, DW sondes are not capable of measuring oxygen even though
a YSI 6562 oxygen probe would be physically compatible with installation in the DW sondes.
Can I measure dissolved oxygen with a DW sonde if I have a YSI 6562 Rapid Pulse DO Probe?
No. Even though the probe will fit in the sonde bulkhead, the polarizing potential from the free chlorine
PC board will not reduce oxygen.
How can I tell the difference between dissolved oxygen and free chlorine sensors?
Along with a different model number stamped on the probe body, the oxygen sensor is built with a gray
body while the free chlorine sensor has a white body.
What are the key competitive features of the YSI Drinking Water Sondes?
• Use hardware, software and sensors (with the exception of free chlorine) which have been proven
in 13 years of surface- and ground-water usage.
• New free chlorine sensor which is easy to calibrate and which has been proven in extensive flow
cell field testing prior to release.
• Relatively small size allows use at virtually any site with a water tap and a drain.
• Easy setup of sonde configuration and calibration of sensors using standard reagents and
techniques.
• Data is compatible with YSI’s widely-used EcoWatch for Windows software for use in custom
data reports and plots.
• Relatively inexpensive compared to wall-mounted systems utilizing separate sensors.
• Can be deployed at remote locations where no AC power is present.
• Good battery life (30 days at a 15 minute sample interval for both 6920DW (with turbidity active)
and for the 600DW-B) under stand-alone conditions.
• Can be used in four distinct modes, all of which have potential use in the drinking water industry.
YSI Incorporated Drinking Water Monitoring Systems Operations Manual H-2