Omron CX-Supervisor, Руководство пользователя

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Data Logging SECTION 11 Data Logging
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11-7-2-5 Deadband
This allows the value of the expression to change within the percentage limit
without being logged. This is particularly useful when logging analogue values
that are subject to noise. Each sample is checked (when the value changes for
'On Change' sampling, or every log period for 'On Interval') against the last
logged value. While the value varies within the deadband, the values are
ignored. When the value exceeds the deadband limits the new value will be
logged. This may dramatically reduce file size, and ease analysis.
Entering a value of 0%, i.e. no dead band, will cause every sample to be
logged.
11-7-2-6 Trigger on change of value
This option is only used when the Sample Rate is set to 'On Change'. When
unchecked, every time the expression changes a new record is written. If a
record consists of many fields that may be read or calculated at different times,
a new record is written every time any one field changes. However, the
desired action may be to change several fields, and then log the new values to
a single record. To achieve this action, the 'Trigger on change of value' should
be checked for all fields within a record that may be read or calculated at
different times. Only when all checked fields have been changed is the record
logged. If however, while waiting for remaining fields to change before writing,
a field is changed for a second time, the record is written with all current field
values including unchanged fields, before the field value is changed for a
second time.
Note: There is a risk when using fields with 'Trigger on change of value' checked that
the new value of a field may not actually change its value i.e. the new value
happens to be the same as the old value. Because the field has not changed,
the record is not written until the value is changed again. This can produce
unexpected results as fields with 'Trigger on change of value' unchecked are
written with their current values at the time of writing, not the value at the time
of initial change. This may also occur when a Deadband is used.