Schlumberger Sema C1SA Manuel D’Utilisation
Operation: C1SD, C1ST, and C1SL Versions
CENTRON Meter Technical Reference Guide
5-23
Classical observation of the open circuit voltage would lead to an overly optimistic
battery life and the likelihood of product failure before the detection circuit
tripped. SchlumbergerSema believes this is a major improvement in design
robustness to classical voltage detect circuitry and will avoid misleading
diagnostics.
battery life and the likelihood of product failure before the detection circuit
tripped. SchlumbergerSema believes this is a major improvement in design
robustness to classical voltage detect circuitry and will avoid misleading
diagnostics.
The curve in Figure 5.8 shows the CENTRON battery usage in amp-hours for the
chosen scenario. The total time over the 15-year life of the product takes a battery
carryover (no power applied) of 1 year (cumulative) and is shown as the initial
year on the graph. In reality, it will likely be spread over the life of the product.
Figure 5.8 shows there is significant margin available for the “on power operation”
at 15 years, even at the 80% limit curve (historically, the low battery would be
flagged at the battery capacity line). When 20% of the battery capacity remains, the
internal resistance starts increasing exponentially, and the current characteristics
of the battery degrades as can be seen from the chart.
chosen scenario. The total time over the 15-year life of the product takes a battery
carryover (no power applied) of 1 year (cumulative) and is shown as the initial
year on the graph. In reality, it will likely be spread over the life of the product.
Figure 5.8 shows there is significant margin available for the “on power operation”
at 15 years, even at the 80% limit curve (historically, the low battery would be
flagged at the battery capacity line). When 20% of the battery capacity remains, the
internal resistance starts increasing exponentially, and the current characteristics
of the battery degrades as can be seen from the chart.
With the assumption that the “low power mode” is used when the meter is not in
field operation (entered from a three button reset), the current drain from the
battery has the same value as the current drain under AC power which means an
increase to the battery life.
field operation (entered from a three button reset), the current drain from the
battery has the same value as the current drain under AC power which means an
increase to the battery life.
A register displays the Low Battery error code (Er 000001) if the minutes-on-
battery counter exceeds 525,600 minutes (1 year). The battery is no longer good
when the Worst Case Battery Usage line crosses the 80% maximum usage line.
battery counter exceeds 525,600 minutes (1 year). The battery is no longer good
when the Worst Case Battery Usage line crosses the 80% maximum usage line.
This means that the battery life for the CENTRON is a conservative estimate of 15
years with or without the 365 days (12 months) of continuous carryover.
years with or without the 365 days (12 months) of continuous carryover.
Meters shipped from the factory unprogrammed or meters removed from the field and given a
3-button reset will not use battery carryover time.
3-button reset will not use battery carryover time.