YSI 6 series Manuale Utente Scaricare il pdf (Pagina 4)

CONDUCTIVITYCALIBRATIONTIPS

BEFORE YOU BEGIN: Verify the accuracy of your temperature probe with a traceable thermometer or

other temperature reference. Temperature compensation is used in every sonde measurement so its

accuracy should be verified and recorded each time the sonde is calibrated.

1. Never calibrate with conductivity standards that are less than 1.0 ms/cm. You are setting the slope on

a linear device so a good strong conductivity signal will give you the best performance. Use 1.0

ms/cm for fresh water, 10 ms/cm for brackish to estuarine, and 50 ms/cm for salt water.

3. Pre-rinse the cal cup and sensors three times with a small amount of the calibration standard or rinse

standard and discard.

4. Insure that the conductivity sensor is completely submerged in standard. The vent hole in the side of

the 6560 probe must be under the solution and sondes with integrated conductivity sensors (600R,

600QS, 600LS, and 600OMS) must also be completely submerged. It is important not to have

trapped bubbles in the cells. Gently shake the sonde to help dislodge any air bubbles that may be

trapped in the conductivity sensor.

5. If the sonde reports “Out of Range” after the calibration, investigate the cause! Never override a

calibration error message without knowing the reason. Typical causes for this error message are

incorrect entries (entering 1000 us/cm instead of 1.0 ms/cm), low solution level, air bubbles in the

probes cell, calibrating in conductivity instead of sp/cond, and/or bad standard.

6. When the calibration has been accepted, check the conductivity cell constant which is located in the

sonde’s “Advanced Menu” under “Cal Constants”. The acceptable range for the 6560 probe is 5 ±

0.45. Numbers outside of this range indicate a problem in the calibration process or with the

standard that was used.

Note: integral conductivity sensors have a higher positive limit. Use the tolerance 0.45 to 0.70 for

QA on 600R, QS, LS, and 600OMS sondes.

NOTICE: The full operating range of the YSI conductivity sensor circuit is 4.0 to 6.0. See the 6-

Series manual for additional information. This means that if you exceed 4.0 or 6.0, you will get an

“OUT OF RANGE” error message which you should never accept. Therefore, for example, never

accept a Cell Constant of 5.9, when the historical Cell Constant has always been around 5.10 to 5.20.

Investigate why you have drastically changed the historical Cell Constant and make attempts to get

the historical Cell Constant back.

CAUTION: The historical Cell Constant may change if changes are done to the probe, for example,

applying anti-fouling paint to the inner holes where the Pure Nickel Electrodes are located will

change your Cell Constant. But, once painted and a new Cell Constant has been established, you

should now be observing near that value for future calibrations.

1 2 3 4 5 6 7 8 9 ... 38 39

Nessun commento

YSI 6 series Manuale Utente Pagina 4