Danfoss VLT FC 100 Series Manual page 31

FC 100/ 200/ 300 DeviceNet
4.4.3. Bus Speed Reference Value under Instances 20/70 and 21/71
The speed reference value is transmitted to
the frequency converter in the form of a 16-
bit word. The value is transmitted as a whole
number. Negative figures are formatted by
means of 2's complement.
The bus speed reference has the following format:
Par. 3-00 = "0" [ref
Par. 3-00 = "1" [-ref
The actual reference [Ref. %] in the frequency converter depends on the settings in the following
parameters:
Par. 1-23
Par. 1-25
Par. 3-03
Note that if the bus speed reference is negative, and the control word contains a run reverse
signal, the drive will run clockwise (- - is +).
Example:
Par. 1-25
Par. 1-23
Par. 3-03
In order to run the motor at 25%, the reference transmitted must be: (1420*0,25) = 355 =
163hex
163hex => 25% => Fout = 12,5Hz
4.4.4. Actual Output Speed under Instances 20/70 and 21/71
The value of the actual speed of the motor is transmitted in the form of a 16-bit word. The value
is transmitted as a whole number. Negative figures are formed by means of 2's complement.
The actual speed value has the following format:
-32767 (8000 Hex) [RPM] -> +32767 [RPM] (7FFF Hex) [RPM]
-> ref ] 0 (0000 Hex) [RPM] =>+ 32767 (7FFF Hex) [RPM]
MIN MAX
-> +ref ] -32767 (8001 Hex ) =>+32767 [RPM] (7FFF Hex)
MAX MAX
Motor Frequency
Motor Nominal Speed
Maximum Reference
Motor Nominal Speed
= 1420 RPM
Motor Frequency
= 50 Hz
Maximum Reference
= 1420 RPM
MG.33.D3.02 - VLT ® is a registered Danfoss trademark
4. How to Control the Frequency Converter
4
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