Emerson Rosemount 389, Reference Manual

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The resulting potentials, measured with a clean platinum electrode and saturated
KCl/AgCL reference electrode, should be within ±20 millivolts of the value shown in
Table 3-1 . Note solution temperature to ensure accurate interpretation of results.
The ORP value of saturated quinhydrone solution is not stable over long periods of
time. Therefore, make these standards fresh each time they are used.
Table 3-1: ORP of Saturated Quinhydrone Solution (Millivolts)
pH 4 solution pH 7 solution
Temp ºC 20 25 30 20 25 30
mV
potential 268 264 260 94 87 80
5. Remove the sensor from the buffer, rinse, and install in the process.
Reference Manual Calibration
00809-0100-3389 February 2019
Reference Manual 29