Rockwell Automation 1440-VST02-01RA XM-120 Eccentricity Module - Manual (Page 110)

Publication GMSI10-UM010C-EN-P - May 2010
102 DeviceNet Objects
The Get_Waveform_Chunk service uses the following request and response
parameters.
Speed Measurement Object
(Class ID 325
H
)
The Speed Measurement Object models a speed measurement of a tachometer
signal.
Class Attributes
The Speed Measurement Object provides no class attributes.
Table C.40 Get_Waveform_Chunk Request Parameters
Name Data Type
Description of Request
Parameters
Semantics of Values
Initial DWORD
Offset UINT The offset of the first 32-bit value
within the data structure to be
returned. 0 <= offset < size of the data structure in
DWORDs.
For example:
offset = 0 refers to bytes 0-3 (the number of
lines or points value)
offset = 1 refers to bytes 4-7 (the FMAX or
period values)
offset = 2 refers to bytes 8-11 (the amplitude
reference value)
offset = 3 refers to bytes 12-15 (the first pair of
normalized values)
offset = 4 refers to bytes 16-19 (the second pair
of normalized values)
....
Number of DWORDs USINT The number of 32-bit values from
the data structure to be returned. This should be small enough to fit in the
explicit message buffer. This will likely be less
than the total size of the data structure so that
several calls to the service will be required to
get the entire data structure.
Table C.41 Get_Waveform_Chunk Response Parameters
Name Data Type
Description of Response
Parameters
Semantics of Values
Number of DWORDs USINT The number of 32-bit values
actually returned in the Data
Chunk array of the response. (Can
be less than the number of
DWORDs requested.) If less DWORDs are returned than were
requested, the end of the data structure has
been reached (the request went beyond the
end of the array).
Data Chunk Array of
DWORD The requested portion of the data
structure.