Hioki MEMORY HiLOGGER LR8450 User Manual

110
Measurement Data
1.17 Measurement Data
The cautions about measurement data are described as follows.
Synchronization and time lag
The instrument and each wireless module have a clock used for sampling data. Plug-in units use
the instrument’s clock as the basis for sampling.
During measurement, di󰀨erences in sampling timing will develop gradually between wireless units
and plug-in units, and between individual wireless units, because the instrument and wireless units
keep time with di󰀨erent degrees of precision.
The instrument periodically corrects for such di󰀨erences between wireless and plug-in units, and
between individual wireless units, even when both wireless and plug-in units are being used.*
In the event wireless communications are interrupted, this correction function will activate once
communications have been restored to correct for di󰀨erences in sampling timing between devices.
*: The di󰀨erence will be about 20 ms with robust wireless communications and more when the
networking signal is weak.
If the system fails the synchronization repeatedly for 40 minutes during measurement, the message
[Sync error] will be displayed in the alarm history.
In this case, the communication state is required to improve.
When the communications between the instrument and the wireless modules recover from
disruption, the number of sampled data points can di󰀨er between the instrument and each wireless
module.
If the numbers of the data points or data sampling times di󰀨er between the instrument and
each wireless module, the system will recover the data using the number of the data points the
instrument sampled and the times when the instrument sampled the data points.
Points where there are di󰀨erences in the data counts or data sampling times can cause data
discontinuity.
See “Synchronization and time lag in acquired data (During Communications Disruption)” (p. 410).
If an outage occurs during measurement
If electric power to only a wireless module is interrupted
• Measured data will contains gaps left during the outage.
• The instrument will draw the horizontal lines along the screen upper end for the data missing
parts of waveforms (regarded as NO DATA).
• When power is restored, the instrument will restart measurement.
If electric power to only the logger is interrupted (When the instrument does not use the
battery power to work)
• The instrument cannot perform measurement.
• No measurement data, even that acquired before the outage occurred, will be retained.
Provided that the auto-save is enabled, the data acquired before the outage occurred will be
retained on the SD Memory Card or the USB Drive.
See “Preparing for power outages and conguring associated settings” (p. 138).
• Even when electric power is restored, the instrument will not restart measurement.
Provided that the start backup or the startup auto-measurement is enabled, the instrument will
restart measurement at the time of power failure recovery.
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Hioki MEMORY HiLOGGER LR8450 Specifications

General

Brand	Hioki
Model	MEMORY HiLOGGER LR8450
Category	Data Loggers
Language	English