Rockwell Automation 1440-VLF02-01RA XM-121 Absolute Shaft Module - Manual (Page 126)

Publication GMSI10-UM014D-EN-P - May 2010
118 DeviceNet Objects
1 These attributes cannot be set for instance 3. The instance 3 settings match the channel 1 settings.
2 This attribute cannot be set for instances 2 or 3. The instance 2 and 3 settings match the channel 1 setting.
7 Get/Set
Time Constant
1
REAL
The detection time
constant associated with
the output smoothing
filter (for the RMS and DC
meters) or the decay rate
of the peak meters. Must be greater than zero.
For RMS type measurements,
the Time Constant attribute
specifies the 3-db bandwidth for
the digital filtering used to
calculate the Overall Value.
The 3-db bandwidth is roughly
equal to (1/Time Constant). The
greater the value of the Time
Constant, the longer the
response of the measured
Overall Value to change in the
input signal.
For Peak type measurements,
the Time Constant value
specifies the decay rate of the
peak detection meter. The
greater the Time Constant value,
the slower the Peak is decayed.
8 Get/Set Damping
Factor
1
REAL The damping factor
associated with output
smoothing filter for the
RMS and DC meters (not
used with peak meters). 0.7072 to 1.0
The Damping Factor is used in
conjunction with the Time
Constant to vary the
characteristics of the response
of the filter used in calculating
the Overall Value. An Overall
Value for a measurement with
Damping Factor near 1.0 will
slowly rise or fall for the full
settling time specified by the
Time Constant before reaching
the final value. An Overall
Value for a measurement with
a Damping Factor near 0.7072
will rise or fall quickly and may
overshoot the final value before
reaching the final value for a
given input signal.
The Damping Factor is only used
in conjunction with RMS
measurement types.
10 Get/Set Low Pass
Corner
Frequency
2
UINT The corner frequency of
the low pass filter.
Note: The instance 1
setting applies to both
channels.
200 to 20000 Hz
Table C.38 Overall Measurement Object Instance Attributes
Attr ID
Access
Rule
Name Data Type Description Semantics