YSI Professional Plus User Manual

Page 25

Sensitivity selected by User

% Data Variance Threshold

100 - Most Sensitive, Sensitivity

bar is set to the far right

0.025%

0.39375%

1.5%

1.13125%

0 - Least Sensitive, Sensitivity

bar is set to the far left

0.15%

Within the Auto Stable menu, you can also

choose to Hold All Readings for as many

parameters as you set for Auto Stable. For

instance, if oRP and pH have Auto Stable

enabled and Hold All Readings is enabled, then

the display will hold the readings once oRP and

pH have both reached their Auto Stable settings.

You must press the Esc key to “release” the held

display in order to take subsequent readings.

Hold All Readings must be reactivated after each use!

CALIBRAtIoN - pH

Calibration can be accomplished in any buffer order. pH

7 buffer should be used regardless of how many calibration

points you use but it does not have to be used first.

Press Cal

. Highlight Probe ID or User ID

if you wish to add, select, edit, or delete an ID.

Probe ID must be enabled in the System GLP

menu to appear in the Calibrate menu. User

ID will appear automatically. Select ‘None’

if you do not want a User ID stored with the

calibration. When enabled, these IDs are stored

with each calibration record in the GLP file.

After selecting your User ID and/or Probe ID if appropriate, highlight ISE (pH)

and press enter. the message line will show the instrument is “Ready for point

1”. the pH calibration allows up to six calibration points.

Place the sensor in a traceable pH buffer solution. the instrument should

automatically recognize the buffer value and display it at the top of the calibration

screen. If the calibration value is incorrect, the auto buffer recognition setting

in the Sensor Setup menu may be incorrect. If

necessary, highlight the Calibration Value and

press enter to input the correct buffer value.

once the pH and temperature readings stabilize,

highlight Accept Calibration and press enter to

accept the first calibration point. the message

line will then display “Ready for point 2”.

If you do not wish to perform a second point,

press Cal

to finalize the calibration. or,

press Esc

to cancel the calibration. If User

Field 1 or 2 are enabled, you will be prompted
to select these fields and then press Cal

finalize the calibration.

to continue with the 2nd point, place the sensor

in the second buffer solution. the instrument

should automatically recognize the second

buffer value and display it at the top of the

screen. If necessary, highlight the Calibration

Value and press enter to input the correct buffer

value. once the pH and temperature readings

stabilize, highlight Accept Calibration and

press enter to confirm the second calibration

point. the message line will then display ‘Ready

for point 3” and you can continue with the 3rd

calibration point if desired.

If you do not wish to perform a 3rd calibration

point, press Cal

to complete the calibration.

If User Field 1 or 2 are enabled, you will be prompted to select these fields and
then press Cal

to finalize the calibration.

Continue in this fashion until the desired number of calibration points is

achieved (up to six).

Once you’ve achieved the desired number of cal points you

must press Cal

to finalize the calibration and to allow the

instrument to update the pH offset and slope. The instrument will

not take these cal values into account until Cal has been pressed.