YSI Pro1020 - Manual (Page 16)

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9. Rinse the sensor and place it in the third pH buffer (4/4.01 or
10/9.18). If necessary, use the up and down arrow keys to adjust
the pH buffer value.
10. Wait approximately 30 to 60 seconds for the pH sensor to
stabilize and for the temperature reading to stabilize. Note the
pH mV reading. pH mVs in buffer 4 should be +159 to 180 mV
from the previous buffer 7 pH mV value. pH mVs in buffer 10
should be -159 to 180 mV from the previous buffer 7 pH mV
value.
11. Press enter to complete the calibration or press Cal to cancel.
12. ‘Calibration Successful’ will display for a few seconds to indicate
a successful calibration and then the instrument will return to
the Run screen.
13. If the calibration is unsuccessful, an error message will display
on the screen. Press the Cal key to exit the calibration error
message and return to the Run screen. See the Troubleshooting
section of this manual for possible solutions.
ORP CALIBRATION
1. Place the clean sensor in ORP calibration solution. Wait for the
ORP and temperature readings to stabilize.
2. Press and hold Cal for three seconds.
3. Highlight ORP and press enter. If ORP is not listed as an option,
check the System Setup menu to ensure ORP is enabled in the
ISE Sensor Type menu.
4. Use the up and down arrow keys to adjust the ORP calibration
solution value.
5. Wait for the temperature reading to stabilize, then press enter
to complete the calibration or press Cal to cancel.
6. ‘Calibration Successful’ will display for a few seconds to indicate
a successful calibration and then the instrument will return to
the Run screen.
7. If the calibration is unsuccessful, an error message will display
on the screen. Press the Cal key to exit the calibration error
message and return to the Run screen. See the Troubleshooting
section of this manual for possible solutions.
T A K I N G M E A S U R E M E N T S
Before taking measurements, be sure the instrument has been
calibrated to ensure the most accurate readings. Turn the instrument
on and wait 5-15 minutes if using a polarographic sensor. Install the
sensor guard to protect the sensors and membrane. If using the 1001A
amplified pH sensor, be sure to use the guard extender supplied in
the 605216 amplified pH sensor kit. The extender is screwed onto the
sensor bulkhead before the guard or cal up is installed.
Place the probe in the sample to be measured and give the probe
a quick shake to release any air bubbles. Be sure the sensors are
completely submerged in the sample.
Dissolved Oxygen
Allow the temperature readings to stabilize. Next, stir the probe in the
sample to overcome the stirring dependence of the dissolved oxygen
sensor. The dissolved oxygen sensor requires at least 6 inches (16 cm)
per second of water movement if using the yellow membrane and
3 inches (7.62 cm) per second of water movement if using the blue
membrane. The required sample movement can be achieved by the
natural flow of the stream, physically stirring the probe in the sample
or a combination of the two. Once the values plateau and stabilize you
may record the measurement and/or store the data set. The dissolved
oxygen reading will drop over time if stirring or movement is ceased. If
placing the DO sensor into a stream or fast flowing waters it is best to
place it perpendicular to the flow and not facing into the flow.
If using the DO sensor near an aeration device, it is helpful to make
sure air bubbles do not burst on the membrane since that may cause
unstable DO readings. You should be able to prevent this by pointing
the sensor upwards so it’s facing the sky and twist tying, zip tying
or rubber banding the bulkhead to the cable. Essentially, making a
simple curve to the cable without bending the cable too tightly will
allow you to place the sensor in the aerated sample while the sensor
points skyward. This measurement method avoids air bubbles bursting
on the DO membrane and results in more accurate dissolved oxygen
measurements.
pH/ORP
pH and ORP readings are typically quick and accurate. However, it may
take the sensors a little longer to stabilize if they become coated or
fouled. To improve the response time of a sensor, follow the cleaning
steps in the Maintenance section of this manual.
S A V I N G A N D V I E W I N G D A T A
The Pro1020 can store 50 data sets in non-volatile memory for later
viewing. A data set includes the values currently on the display, i.e.