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Rockwell Automation Publication 1440-UM001D-EN-P - September 2016 153
CIP Objects Appendix B
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.
Instance Attributes
Services
Table 82 - Speed Measurement Object Instance Attributes
Attribute ID Access Rule Name Data Type Description Semantics
3 Get Speed Value REAL The measured speed value. CPM
4 Get Status BOOL Indicates if a fault or alarm has occurred. 0 = Operating without alarms or faults.
1 = Alarm or fault condition exists. The Speed Value
attribute does not always match the actual field
value.
5 Get Maximum Speed REAL The maximum (peak) measured speed
value since the most recent reset.
CPM
12 Get/Set Time Constant UINT The time constant value that is used for
exponential averaging of the Speed Value
(a low pass filter/output smoothing filter).
Milliseconds
13 Get Acceleration REAL The rate of change of the Speed Value. CPM/min
14 Get/Set Measurement Response USINT Determines how quickly the Speed
measurement responds to change. For
example, setting this attribute to 1
indicates a settling time of 220 ms. The
speed is averaged over a quarter second,
and the reported value reaches 90% of the
new steady state value about 220 ms after
the change in machine speed. See this table.
Meas.
Response Settling
Time Time
Constant
0 2640 ms 1200 ms
1 220 ms 100 ms
2 22 ms 10 ms
Table 83 - Speed Measurement Object Services
Service Code Class/Instance Usage Name Description
05
h
Instance Reset Clears Maximum (Peak) speed to 0.
0E
h
Instance Get_Attribute_Single Returns one attribute.
10
h
Instance Set_Attribute_Single Sets one attribute.
(1)
(1) Attributes can only be set while the device is in Program mode. See the description of the Device Mode Object for more
information.