Teledyne LXT-230 manual Sentinel Diagnostics, Diagnostic set up and configuration menus, Main Menu

4.0 SENTINEL DIAGNOSTICS

The basic menu structure of the LXT-230 transmitter is architecturally the same as the LXT- 230 pH, ORP and PION, with the only variable being the diagnostic information on the main and special diagnostic menus. The critical path to your process measurement is via the TAI sensor/electrode.

Under perfect conditions, the electro-chemical interface between the electrode’s internal reference cell (the measurement standard) and the liquid junction (bridge between the internal electrolyte and the wet process) should be in balance (stable potential values). However, a dominant failure mechanism of an Electro-Chemical(pH, ORP, PION) Reference Half Cell is insidious process contamination impacting that balance (electrode internal chemistry).

Contamination from the wet process will eventually migrate through the electrode’s inner structure eventually changing Electro-Chemical balances via oxidation/reduction of the metal/metal salts and gels.

4.1 Diagnostic set up and configuration menus

4.1.1 Main Menu

The degree to which the intrusive process chemicals degrades the “insitu” electrode is graphically depicted on the right side of the LXT-230 main process screen as a vertically expanding diagnostic bar, culminating in a flashing pre-pHault alert. This pre pHault Alert warns the user of a pending chemical alteration of the Electro-Chemical Reference Measurement Cell prior to the actual measurement error, hence the designation, “Pre- pHault.”

pH	7.00
_50.0%	25.0°C

ORP	100.0 mV
25.0%	25.0°C

4.1.2 SENTINEL DIAGNOSTIC SCREEN

The lower section of this (split screen – over under) menu will indicate default mV values as set by the factory; the default value will be 60mV in all cases. This value is Nurnstian in that it signifies one decade change in 4 molar reference gel. The transmitter has been designed so that the customer can input other mV values based on individual experience that may differ from the default mV number.

Ref	25.2 mV
Limit	30.0 mV

To change the “LIMIT” values, enter the CALIBRATE MODE by simultaneously pressing the two horizontal CALIBRATE keys; observe the cursor move to the right allowing LIMIT value change. Once in CAL MODE, the cursor can be moved to different digit placements, then, using the vertical key, the LIMIT value can be decreased or increased based on process demands.

NOTE:

This value responds to contamination of the secondary electrolyte chamber with a Nurnstian response (log 10 System)

Model LXT-230 Instruction Manual / 10