Important Considerations

1. Stray DC voltages (1 to 5 volts) should not affect the accuracy of pH/ORP measurement.
2. The pH needs to be closely controlled for optimum production in a very energy intensive     process.
3. The system should perform for long periods of time: 1) without recalibration; 2) despite     precipitate buildup     on the sensor; 3) without reference diluion effect.
4. The sensor must also perform under these adverse conditions:
.   High temperatures (90 OC) that are variable
.   High sodium (Na +) ion concentration (maintain linearity)
.   Presence of corrosive chemicals (NaCI, NaCIO 3, NaOCI, CI 2, HCI)



The preceding considerations for pH/ORP measurement call for instruments based on BI's Differential Electrode Technique of measurement. The following features address the crucial needs for successful measurement.

pH/ORP Sensor : Differential Electrode Measurement Technique. Fast response. Bufered reference solution . Special glass for high alkaline pH . Excellent chemical resistance (LCP-encapsulated)

pH/GAP Transmitter : .Microprocessor-based . Buffer sensing calibration . Diagnostic error messages.


Typical BI pH and OAP systems consist of :

A. One pH sensor (Model 7028P0C)
B. One ORP sensor (Model 3028P0C) One ORP transmitter (Model 692R)



Field experience has shown that the Differential Technique is the method of choice in pH/ORP measurement. Conventional sensor measurements are erratic, even with a current interrupter.