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G7 ASD Multi-Protocol Communication Option and PG Feedback Option Manual
69
When the ODVA AC/DC drive profile standard I/O assembly instances are active, the same concept
detailed in the previous paragraph applies, except that the first half of the AC/DC drive object attributes
are coupled to the actual ASD operation, and the second half of the attributes are decoupled (and should
therefore be ignored).
11.5.8.6 AC/DC Drive Object Attribute Semantics
This section will detail any specific information that may be useful when accessing the attributes of the
AC/DC Drive Object, whether directly via explicit messaging or indirectly via I/O assembly objects.
AtReference
This attribute is “1” whenever SpeedActual is within ±1 RPM of SpeedRef.
NetRef
Maps directly to the “speed reference priority” bit (bit #14) of the G7 command word (refer to
G7
Command Word
below). When this attribute (and therefore command word bit #14) is “1”, the option
frequency command (derived from SpeedRef when AC/DC drive profile I/O assemblies are active)
becomes the drive’s active frequency command, regardless of the ASD’s
Frequency Mode
selection
parameter. When this attribute is a “0”, the option frequency command will no longer override the
Frequency Mode
selection parameter, but the option frequency command may still be used by the ASD
as its overall frequency command if the
Frequency Mode
selection parameter is set to “
Use
Communication Card (option)
”.
DriveMode
This attribute has no effect on drive operation: values written to it are for user reference only.
SpeedActual
The SpeedActual attribute is the motor’s synchronous operating speed in RPM, and is calculated using
the following formula:
PolesMotor ofNumber
(Hz)Frequency Output x 120
Int = lSpeedActua
,
where “Output Frequency” is the inverter’s current operating frequency and “Number of Motor Poles” is
the value contained in the PoleCount attribute of the Motor Data Object (refer to section 11.5.7). Only
the integer portion of the calculated result will be transmitted across the network.
SpeedRef
The SpeedRef attribute value is used in the following calculation to determine the ASD’s option
frequency command value:
120
PolesMotor ofNumber x SpeedRef
=(Hz) CommandFrequency
,
where “Number of Motor Poles” is the value contained in the PoleCount attribute of the Motor Data
Object (refer to section 11.5.7).
RefFromNet
This attribute mirrors the value set in attribute #4 “NetRef”.
Frequency Command
Unsigned 16-bit value whose value is the desired ASD option frequency command multiplied by 100.
For example, if a frequency command of 55.34Hz is desired, then 55.34 x 100 = 5534
10
(0x159E). If
the frequency command exceeds limiting drive parameters (such as the
Upper Limit Frequency
or
Maximum Frequency
), then the drive will ignore it, maintaining its current setting.
Command Word