<12. Troubleshooting>
12-8
IM 11M12A01-04E 11th Edition : Jul. 19, 2017-00
l Alarm 13: Battery Low Alarm
An internal battery is used as backup for the clock. After this alarm occurs, removing power from
the instrument may cause the clock to stop but should not affect stored parameters. The internal
clock is used for calibration and purge scheduling; if you use this then after a battery alarm occurs
(until the battery is replaced) be sure to check / correct the date and time every time you turn on
the power.
<Corrective action>
When the battery low alarm occurs, remember that the battery cannot be replaced by the user.
Contact your Yokogawa service representative.
NOTE
Battery life varies with environmental conditions.
* If power is applied to the instrument continuously, then the battery should not run down, and
life is typically about ten years. However the battery will be used during the time interval
between shipment from the factory and installation.
* If power is not applied to the instrument, at normal room temperatures of 20 to 25°C then
battery life is typically 5 years, and outside this range but within the range -30 to +70°C then
battery life is typically 1 year.
12.3 Measures When Measured Value Shows an
Error
The causes that the measured value shows an abnormal value is not always due to instrument
failures. There are rather many cases where the causes are those that measuring gas itself
is in abnormal state or external causes exist, which disturb the instrument operation. In this
section, causes of and measures against the cases where measured values show the following
phenomena will be described.
(1) The measured value is higher than the true value.
(2) The measured value is lower than the true value.
(3) The measured value sometimes shows abnormal values.
12.3.1 Measured Value Higher (Lower for Humidity Analyzer)
Than True Value
<Causes and Measures>
(1) The measuring gas pressure becomes higher.
The measured oxygen concentration value X (vol% O
2
) is expressed as shown below, when
the measuring gas pressure is higher than that in calibration by Dp (kPa).
X=Y [ 1+ (Dp/101.30) ]
where Y: Measured oxygen concentration value at the same pressure as in calibration
(vol% O
2
).
Where an increment of the measured value by pressure change cannot be neglected,
measures must be taken.
Investigate the following points to perform improvement available in each process.
Is improvement in facility’s aspect available so that pressure change does not occur?
Is performing calibration available under the average measuring gas pressure (internal
pressure of a furnace)?
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