YSI 6000UPG - Manual (Page 169)

H-5
or negative) if the probe is responding correctly from an optical standpoint. If no response is
noted, the probe must be returned to YSI Customer Service for repair or replacement.
CAUTION: DO NOT ATTEMPT TO DISASSEMBLE THE PROBE YOURSELF. If the probe
is functioning properly, replace the probe guard and place the sonde back into 0 NTU water.
Activate the wiper or agitate the sonde rapidly to remove bubbles and enter the calibration
routine of choice (1-, 2-, or 3-point) from the Calibrate menu. Observe the readings for the 0
NTU standard. If values higher than about 5 NTU are observed, it is possible that your 0 NTU
standard has been contaminated from debris which was retained on the sonde and probes from
the previous field usage. Discard the water, rinse the sonde, and replace in new 0 NTU standard.
After agitation, check the reading to see if it has been reduced. If so, proceed with the second
calibration point. If not, contact YSI Customer Service for further assistance. If a calibration
error occurs on the second point, use a new source of standard and try again. If an error still
occurs, contact YSI Customer Service for further assistance.
You might observe readings during sampling which appear unreasonable from visual
inspection of the water. The problem is almost always caused by bubbles on the optics.
Activate the wiper or agitate the sonde remove the bubbles. If the readings are still unreasonable,
remove the sonde completely from the water and then replace in the water. If problems are still
evident, remove the sonde guard and check general probe function by placing your finger or
thumb over the optics as described above. If the probe does not respond, contact YSI Customer
Service.
You might see readings during sampling which you think are too jumpy. If this occurs, the
water may be nonhomogeneous with regard to the size of the suspended particles. The jumpiness
which you are observing is probably real. However, if you want to smooth it out, you can
incrementally increase the value of “Number of Samples to Average”. Remember, that this will
result in an increase in the response time of the turbidity sensor so you will be required to wait
longer before recording readings.
You might observe single point spikes in data from deployment applications. These high
readings may be real turbidity events caused by large particles passing over the optical surface at
the time of measurement. As long as the spiking occurs only occasionally, there is no reason to
believe that the turbidity system is malfunctioning. Depending on the site, these spikes may be a
normal occurrence.
You might see a lot of positive and/or negative spikes in data from deployment
applications. This symptom usually results from improper activation or parking of the wiper
assembly. If it occurs with a new wiper assembly, make certain that the wiper rotates and parks
correctly (opposite the optical surface) in 0 NTU standard. If the wiper does not rotate at all, be
certain that the setscrew of the assembly is contacting the flat part of the shaft and that the screw
is securely tightened using the small hex key which is supplied with the wiper assembly. If the
wiper still will not rotate on manual activation, contact YSI Customer Service. If the problem
occurs with a wiper assembly which has been in the field for some time and is discolored or
abraded, install a 6027 replacement with a new pad, assure function and correct parking in 0
NTU standard, and redeploy. If a high frequency of spikes still occurs in the deployment data,
contact YSI Customer Service for further assistance.