Rockwell Automation 1440-VSE02-01RA XM-122 gSE Vibration Module - Manual (Page 179)

Publication GMSI10-UM013D-EN-P - May 2010
DeviceNet Objects 169
The total size of the Waveform Data structure in DWORDs is: 3 + (Number
of Waveform Points / 2)
The Waveform Data is an array of INT (16-bit signed integers ranging from
-32768 to 32767). The number of INTs in the Waveform Data array is equal to
the Number of Waveform Points. To convert the normalized Waveform
Data into floating point values, use the following equations:
Where Float Data
n
is the value for the nth waveform point, and 0 ≤ n ≤
Number of Waveform Points.
The Get_Spectrum_Chunk and Get_Waveform_Chunk services use the same
request and response parameters.
Float Data
n
Amplitude Reference
Normalized Data
n
32768
----------------------------------------------- =
Table C.56 Get_Spectrum_Chunk/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.