Emerson Rosemount 3900 Quick Start Manual page 24

Quick Start Guide
quinhydrone solution is not stable over long periods of time.
Therefore, make these standards fresh each time they are used.
Table 2-1: ORP of Saturated Quinhydrone Solution (Millivolts)
pH 4 solution
Temperature: 68 (20)
°F (°C)
mV potential 168
3. Remove the sensor from the buffer, rinse, and install in the process.
2.5 Maintain oxidation reduction potential (ORP) sensors
Electrodes should respond rapidly. Sluggishness, offsets, and erratic
readings are indicators that the electrodes may need to be cleaned or
replaced.
1. To remove oil deposits, clean the electrode with a mild non-abrasive
detergent.
2. To remove scale deposits, soak electrodes for one to five minutes in a
5 percent hydrochloric acid solution.
3. Polish ORP (metallic) electrodes with moistened baking soda.
24
77 (25) 86 (30)
264 260
pH 7 solution
68 (20) 77 (25)
94 87
Emerson.com/Rosemount
November 2020
86 (30)
80