PROTOCOL-SPECIFIC INFORMATION
Drive State: Indicates the current state of the Control Supervisor Object state machine. Refer to the
ODVA EtherNet/IP specification (object library) for detailed information on the Control Supervisor Object
state machine.
Speed Actual: Inverter operating speed in RPM. Maps to inverter register 201 (output frequency). The
output frequency value read from the inverter depends on the settings of parameters Pr. 37 and Pr. 144
(refer to
Table 32). The speed actual component of the AC/DC drive profile input instances is always in
units of RPM. With certain combinations of Pr. 37 and Pr. 144, however, the inverter provides its output
frequency either as an actual frequency (with units of Hz) or as a speed (with units of RPM). Therefore,
the interface card will apply a Hz-to-RPM conversion equation when necessary, or will pass the
inverter’s output frequency value directly on to the network as-is when the inverter is already providing
the output frequency in units of RPM.
The Hz-to-RPM conversion equation is [output frequency x 120 / number of motor poles]. Table 32
indicates the scenarios under which the conversion equation is and is not applied, and the value used
for the “number of motor poles” component in the denominator of the conversion equation. For more
information on the manners in which Pr. 37 and Pr. 144 affect the inverter’s operation, please refer to the
appropriate inverter user’s manual. Note that the values of Pr. 37 and Pr. 144 are read by the interface
card only at boot-up, so if these parameter values are changed, then the interface card must be
rebooted in order for it to recognize the new values and once again determine the required conversion
scenarios.
9.2.7 Explicit Messaging Via Get/Set Attribute Single Services
Get attribute single (0x0E) and set attribute single (0x10) are common services that can access the
inverter registers by specifying the appropriate class code, instance number and attribute identifier. The
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