15 Calibration Procedures; 2-Electrode Conductivity - ABB AWT420 Operating Instruction

AW T4 2 0 | U N I V E R S A L 4 - W I R E , D U A L- I N P U T T R A N S M I T T E R | O I/A W T4 2 0 - E N R E V. B

15 Calibration procedures

2-electrode conductivity

Menu
Calibrate
Exit Select
Menu Comment
Conductivity Cal See typical procedure, see page 56.
Concentration Cal
See typical procedure, see page 56.
Resistivity Cal See typical procedure, see page 56.
Temperature Cal
See Temperature Calibration procedure, see page 69.
Edit Cal
PV Slope Edit the PV Slope value.
• Valid slope values range from 80 to 120 %
PV Offset Edit the sensor PV Offset.
Valid offset values are:
• ±20 µS/cm for cell constants of 1.00
• ±4 µS/cm for cell constants of 0.10
• ±0.8 µS/cm for cell constants of 0.01
Edit the Temperature Slope value.
Temperature Slope
• Valid slope values range from 40 to 160 %
Temperature Offset Edit the Temperature Offset value.
• Valid offset values are ±40 °C.
Restore Cal Defaults Resets slope and offset values to factory default.
The conductivity/concentration/resistivity/temperature calibration is a smart one-point
calibration routine that allows for single- or dual-point calibrations. By initiating calibrations at
two different conductivity/concentration/resistivity/temperature values having ample
separation, the AWT420 transmitter automatically adjusts the offset, slope, or both in order to
obtain the best sensor performance. Since this routine only uses the most recent calibration
data, calibration can be conducted throughout the sensor's life thus ensuring consistent sensor
performance. If an incorrect calibration has been entered, the Restore Cal Defaults menu
returns transmitter calibration values to factory settings.
The AWT420 transmitter can be configured as a Conductivity, Resistivity or Concentration
device, the smart one-point calibration routine automatically uses the same units as the
measured process variable.
Note. Access the calibrate menu via the Calibrate and Advanced levels only.
55
Default
N/A
N/A
N/A
N/A
100 %
0 µS/cm
100 %
0 °C
N/A