Yokogawa 2-Wire Dual Channel Transmitter/Analyzer FLXA21 - Manual (Page 120)

<9. OPERATION OF ISC (Induvtive Conductivity)>
9-8
IM 12A01A02-01E 5th Edition : Oct. 31, 2013-00
n Last calibrated
= date on which the last sensor calibration was performed. The displayed value of the Zero is the
result of this calibration. The displayed value of Slope was calibrated on this date only if the last
calibration was a 2-point calibration.
n Calibration due
= the date when the calibration must be done next according to the settings of the calibration
interval. The calibration intervals are set in Commissioning → Measurement setup → Calibration
settings → Limits and timing.
n Projected replacement
The projected maintenance function predicts the date when the sensor unit will need cleaning or
recalibrating for maintaining measurement accuracy. The function checks the cleanliness of the
sensor by monitoring the cell constant after calibration. Clean the sensor before the predicted
date.
The function predicts the dates when the cell constant will cross the upper or lower limits and
displays the predicted date with the status (the status is displayed in parentheses).
As shown in Figure 9.6, the date is predicted based on the intersection point of the upper or lower
limits and the extrapolated line of the values obtained by the least squares method.
Day
Value
Lower limit
Upper limit
Current
date
Projected
maintenance date
F0310.ai
Figure 9.6
The status shows the certainty of the projected maintenance date in terms of the correlation
coefficient R. Tables 9.1 and 9.2 show respective display patterns.
Table 9.1 Display pattern of the projected maintenance date
Projected date - - 0-1 month 1-3 months 3-6 months 6-12 months Over 1 year
- - : cannot be predictable due to insufficient data
Table 9.2 Display pattern of the status
Status
(- - - - -)
(R < 0.50)
(Poor)
(0.50 ≤ R < 0.70)
(Reasonable)
(0.70 ≤ R < 0.85)
(Excellent)
(0.85 ≤ R < 1.00)
n ISC module (sensor)
With this screen, you can check the module productions number and software revision of the
installed module.
n HOUSING ASSY
With this screen, you can check the module productions number, software revision, and HART
device revision of the housing assembly.