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)