Nova-Tech 2700 Series Benchtop Meters - Manual (Page 20)

16
7. Millivolt (mV) Calibration (Offset Adjustment)
Oxidization Reduction Potential (ORP or Redox) as measured by an ORP
electrode in mV units is not a precise measurement, but is useful as a relative
indicator. As such, mV offset adjustment is not meant to enhance accuracy, but
rather to make readings comparable to a reference.
Commercial ORP solutions are commonly used as a check standard—a
meter/electrode system is verified to be close to a given value although
adjustments are not made. These solutions can be used as a calibration standard
in which adjustments are made in an attempt to match the ORP value, however
results are often difficult to reproduce.
1) Turn meter on, connect an ORP electrode, and press MODE if needed for mV
(or R.mV) measurement.
2) Dip the ORP electrode into a solution with a known mV value (i.e. Zobel,
Light’s, quinhydrone, or iodidetriiodide) with brief or slow stirring.
3) Press CAL when the reading is stable. The upper display shows the active
millivolt value (mV) while the lower display shows the factory default mV value
without calibration. The example below at right shows a mV calibration that
had previously been calibrated with a 10.0 mV offset.
4) Adjust the upper display using up/down arrows, press ENTER to accept the
calibration offset. The maximum adjustable value is ±150 mV from the factory
default mV value.
Additional mV calibration notes:
When an offset has been stored successfully, R.mV replaces mV in measurement
mode.