Somat eDAQlite, Руководство пользователя

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I2773-4.
4
en 123
Somat eDAQ
lite
Stale Data Expiration
Set the data expiration time period in seconds. If the specified time elapses before the
receipt of a data update on the input channel, the eDAQ
lite
flags the data as invalid.
NOTE
If the expiration time period is less than the sample rate period, the eDAQ
lite
overrides the value and sets it such that the data will not expire in one sample period
or less.
Invalid Data Output Value
Set the value to substitute for any data flagged as invalid. If the data type is 32-bit float,
the substitution value can be any floating point value; otherwise, the substitution value
must be in the range of the full range min and max values specified for the channel in
the database definitions.
Bus channel inputs can be invalid for a number of reasons. The data may be marked
as invalid when the eDAQ
lite
interface receives the data (e.g., the data may not be
available at the source, the data may be marked as out of range at the source, etc.).
NOTE
The invalid value is defined in terms of the raw signal units as specified in the database
definition. Subsequently scaling the output (e.g., by using calibration definitions that
convert units) also scales the invalid value accordingly.
Raw Data Type
The raw data type is typically the data type defined in the database (i.e., 8-bit
unsigned, 16-bit unsigned or 32-bit unsigned). However, for database bit sizes other
than 8, 16 or 32, the eDAQ
lite
promotes the raw data type to one of these three bit
lengths. For example, a 1-bit unsigned is promoted to 8-bit unsigned and a 24-bit
unsigned is promoted to 32-bit unsigned.
Convert Raw Data to 32-Bit Float
Select the convert option to set the output data type to 32-bit float. The conversion
adds some computational overhead, but this is relatively insignificant to overall
eDAQ
lite
performance at the low sample rates typically used for bus inputs.
6.6.2 Vehicle Bus Message Channel
Use vehicle bus message channels to acquire raw vehicle bus packets. After selecting
the desired channel type, complete the ID, connector and description fields. For more
information on vehicle bus message channels, see
“Vehicle Bus Message” on
page 99 .
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