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Language Dictionary - 6
85
The measurement log contains measurements acquired during the forming sequence. For the
sequence step types CF_CHARGE, CF_DISCHARGE, or CF_REST, a log entry is made at the
beginning and end of a step. Additional log entries are made whenever the voltage, current, or
time meet the criteria specified by the function cfSetMeasLogInterval. For all other sequence
step types, only one entry is made containing a specific measurement.
The value pointed to by the read_pos argument controls which portion of the log is read. If this
value is the special value CF_READ_FIRST, data is returned starting at the beginning of the log.
Subsequent calls to cfReadMeasLog use the location pointed to by read_pos to keep track of the
read position. If the value pointed to by read_pos is the special value CF_READ_LAST, the last
entry for the specified cell is returned. If this special read_pos value is combined with the cell
argument of CF_ALL_CELLS then the last 256 entries in the log are returned if bufsize is large
enough to accept them. If bufsize is not large enough, the last entries that fit in bufsize are
returned.
The cell and step arguments act as filters that allow limiting the returned log entries to a specific
cell or specific step numbers. The cell argument can be an individual cell number from 1 to 256,
or the constant CF_ALL_CELLS to read log entries for all cells. The step argument can be an
individual step number, or the constant CF_ALL_STEPS to read log entries for all steps.
Additional step arguments return tagged measurements. The following table summarizes the step
arguments:
<step number>
returns entries for that step number
CF_ALL_STEPS
returns entries for all steps
CF_STEP_TRANSITIONS
returns summary entries of each step
CF_TAGGED_ACR
returns tagged ac resistance entries
CF_TAGGED_DCR
returns tagged dc resistance entries
CF_TAGGED_OCV
returns tagged open circuit voltage entries
CF_TAGGED_CUM_AH
returns tagged cumulative ampere-hour entries
CF_TAGGED_CUM_WH
returns tagged cumulative watt-hour entries
If the step argument is the special value CF_STEP_TRANSITIONS, the function returns a very
abbreviated number of entries from each step. This can be used to obtain a quick summary of a
sequence. For steps of type CF_CHARGE, CF_DISCHARGE, or CF_REST, it returns an entry
at the beginning of the step and the last entry in the step. For all other sequence step types, it
returns a single entry.
The number of characters read into the buffer is returned in retcount. cfReadMeasLog will not
return a partial measure log entry, so the number of characters read will typically be slightly less
than the buffer size. When the retcount value is 0, the end of the measure log has been reached.
Reading the entire measurement log can be time consuming if the forming sequence is long and
the logging intervals are set for frequent entries. There is an optimum buffer size that should be
used if maximizing the reading speed is important. The macro CF_MEAS_LOG_BUFSIZE is
provided in the header file mccd.h for this purpose, and can be used as shown in Example 1 in
chapter 7.
Measurement log entries are sequences of ASCII formatted values separated by ASCII tab (’\t’)
characters. Each log entry is terminated by a newline (’\n’) character. The format of a
measurement log entry depends upon the step type of the corresponding sequence step. All log
entries are the same format in the first 4 values, but the meaning of subsequent values depend on
the step type.