Mettler Toledo SevenCompact S220 Instrucciones De Manejo página 33

The measured signal should not change by more than 0.1 mV in 6 seconds.
Fast
The measured signal should not change by more than 0.6 mV in 4 seconds.
- Stability criterion for ion measurement
Strict
The measured signal should not change by more than 0.03 mV in 12 seconds or by more than
0.08 mV in 26 seconds.
Medium
The measured signal should not change by more than 0.08 mV in 8 seconds.
Fast
The measured signal should not change by more than 0.3 mV in 4 seconds.
Ion Measurement Units
The ion concentration unit for measurements and calibration can be selected between the following
six units: mmol/L, mol/L, ppm, mg/L, %, pX.
In some cases, changing measurement units requires the user to first recalibrate before starting a
mea s ure m ent, otherwise an error message will appear. The units of measurement are divided in
two groups: 1. mmol/L, mol/L and pX, and 2. ppm, mg/L, %. Changing within a group does not
require calibration, but changing between the two groups does.
Ion Type
When using an ion sensor to which previously a sensor ID has been assigned, the ion type that
has been assigned to this sensor ID is automatically used.
However, in case one would like to measure without a sensor ID, it is important to assign the cor-
rect ion type. This is because the theoretical slope depends on the charge of the ion (see below)
Eight specific and four general ion types are available:
F (fluoride), Cl (chloride), CN
- -
(Cal c i u m), Cu (cuprous), Ion
2+
Depending on the type of electrode the theoretical slope differs due to the charge of the ion. The flu-
o r ide electrode has e.g. a theoretical slope of +59.16 mV/pX whereas the theoretical slope of a
cal c i u m electrode is -29.58 mV/pX. This theoretical value is loaded for a new entered sensor ID
until the sensor is calibrated.
Rel. mV Offset
In the rel. mV mode the offset value is subtracted from the measured value. Either an offset value
can be entered or it can be determine by measuring the mV of a reference sample.
Offset value
●
Enter an offset value in mV between -1999.9 and +1999.9 mV.
(cyanide), NO (nitrate), Na
- 3-
, Ion , Ion and Ion .
- + 2- 2+
(sodium), K (potassium), Ca
+ +
Menus and settings
2+
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