EN-67
Thermo Scientific Orion Star
™
and Star Plus Meter User Guide
Appendix A
Meter Setup Menu Features
pH Setup Menu Features
Automatic Buffer Recognition
The Orion Star and Star Plus pH meters are capable of automatically recognizing pH
1 .68, 4 .01, 6 .86, 7 .00, 9 .18, 10 .01 and 12 .46 buffers during a pH calibration . During
a calibration, the meter uses the selected buffer set and the raw mV reading of the
pH electrode in the buffer to recognize and display the buffer value at the measured
temperature . The raw mV value must be about ± 30 mV from the theoretical mV
reading of the buffer in order for the meter to automatically recognize the buffer .
Buffer
mV Range
Buffer
mV Range
Buffer
mV Range
1.68
+285 to +345
7.00
- 30 to + 30
10.01
-207 to -147
4.01
+207 to +147
9.18
-99 to -159
12.46
-293 to -353
6.86
+38 to -22
Dissolved Oxygen Setup Menu Features
Barometric Pressure Compensation
The Orion Star and Star Plus dissolved oxygen meters have an internal barometer
that is used for pressure compensated dissolved oxygen readings . The meter can
also use manual barometric pressure compensation if dissolved oxygen is measured
with a submerged probe or in a pressurized vessel . The pressure must be entered
as mm Hg . 1 mm Hg = 0 .03937 inch Hg = 1 .3332 hPa (mBar) = 0 .01934 PSI .
Salinity Correction
Automatic salinity correction for dissolved oxygen readings is available on Orion
Star and Star Plus dissolved oxygen meters that have a conductivity measurement
mode . The meter uses the conductivity value read by the conductivity probe to
calculate the salinity correction factor and applies the factor to dissolved oxygen
readings reported as mg/L .
The meter can also use manual salinity correction for dissolved oxygen readings
reported as mg/L . The manual salinity correction factor must be entered as ppt
(parts per thousand) .
