IM 12A06S01-00EN-P
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•
Predictive sensor replacement
, which predicts the date when the sensor will need
replacement. The date is based on the pH ZERO and pH SLOPE on each calibration, and
the measured low-ohmic reference impedance. The date is predicted based on the best
status of correlation in those three parameters. If some parameters have the same status,
the nearest date is selected. The function indicates the date and its reliability status.
3.4.6 Sensor wellness
The SA11 can calculate the performance status of the sensor connected. The calculated
result depends on user programmable settings done in the Yokogawa HOST system, and
the sensor diagnostics data stored in the ID-chip of the sensor.
When a sensor is replaced or exchanged, a reset of the wellness data is not necessary. If a
user wants to reset this data anyhow, this is possible by the Yokogawa HOST system. For
details see the belonging User’s Manual.
There are seven (7) different wellness statuses for pH:
• ZERO
• SLOPE
• IMP1
• IMP2
• Progress time
This is the time in between 0 and actual operating hours of the sensor.
• Heat cycle
This is a counter which counts the settable temperature step changes (up or down) of a
sensor.
• Total
This state indicates the worst wellness state of those activated.
Each wellness status can be set ON or OFF. If activated, the status is measured as a ratio of
the actual value against the calculated value obtained from settings of lower limit and upper
limit. For limit setting see Appendix 1. The status is indicated as a number in between 0
(bad) and 4 (good).
3.4.7 Sensor status
The SA11 monitors some process conditions of the connected sensor:
•
Maximum temperature exposed
, which is automatically updated every time a higher
process temperature is measured.
•
High temperature 1/High temperature 2
, which is the total time at which the sensor
is exposed above the corresponding limits, set by the Yokogawa HOST system. The last
date and time (the end of high-temperature condition) is stored.
•
Sterilization
, which reflects the number of times at which the temperature remains above
the preset value for at least the prescribed time period set by the Yokogawa HOST
system.