Teledyne LXT-230 manual Main Menu, Electrode Diagnostic Screen, Electrode Standardization Menu

3.2.2 Main Menu

This menu appears after the Copyright Display when power is first applied to the LXT-230. The Main Menu displays the measured process variable, temperature, and the current output in percent of full-scale. While in this menu, the current output can be adjusted and locked in a manual mode to provide an undisturbed output during buffer calibrations.

pH	7.00
_50.0%	25.0°C

ORP	-500.0 mV
_25.0%	25.0°C

3.2.3 Electrode Diagnostic Screen

As an informational screen only, this display provides diagnostic data pertaining to the electrode. The top line displays the real-time (active) absolute millivolt value (mVa) the electrode is generating, not compensated for temperature variations. The bottom line displays the electrode isopotential from the last calibration. The isopotential (electrode offset) is the value at which the electrode output is zero millivolts. A perfect pH electrode will indicate an isopotential of 7.00 pH. Replace the electrode if the isopotential is less than 6.00 pH or greater than 8.00 pH.

Input	.0 mVa
0 mVa	7.00

Input	-500.0 mVa
0 mVa	.0 mVa

A perfect ORP electrode will indicate an isopotential of 86 mV @ 25°C. Replace the electrode if the isopotential is less than 36 mV or greater than 136 mV @ 25°C.

This information is extremely helpful in determining the diagnostic status of a pH or ORP electrode. In conjunction with regular calibrations, the Electrode Diagnostic Screen provides valuable information to track electrode performance.

3.2.4 Electrode Standardization Menu

Provides the means with which to perform a one-point calibration (standardization) or the first point of a two-point calibration. For pH this point is typically 7.00 pH and ORP this point is typically 0.00 mV.

1 pH	7.00
Cal	.0 mV/pH

1 ORP	.0 mV
Cal	.0 mVa

Before entering the calibrate mode, the menu provides historical data from the last calibration. The top line displays the buffer, or calibration point, at which the last calibration was performed. The bottom line displays the temperature compensated mV value the electrode generated at the buffer point. Please note that temperature compensation is not performed for ORP. When in the calibrate mode, the bottom line displays the real-time, or active, millivolt value.

3.2.5 Electrode Span Menu

Provides the means to perform the span calibration, or the second point of a two-point calibration. Before entering the calibrate mode, the menu provides historical data from the last calibration.

2 pH	.00
Cal	-59.1 mV/pH

2 ORP	.0 mV
Cal	1.000 mV / ORP

Model LXT-230 Instruction Manual / 8