Present Output Frequency - Danfoss VLT 2800 Design Manual

Programming
Illustration 4.34 Control Word and Reference
The frequency converter is to receive a start command and
the reference is to be set to -50% (-2000 Hex) of the
reference range.
The reference value is first converted to 1' complement,
and then 1 is added binarily to obtain 2' complement:
2000 Hex
1' complement
2' complement
Table 4.17 Reference Value
Control word = 047F Hex ⇒ Start command.
Reference = E000 Hex ⇒ -50% reference.
Illustration 4.35 Resulting Control Word and Reference

4.7.11 Present Output Frequency

Illustration 4.36 Present Output Frequency
The value of the frequency converter's present output
frequency is transferred as a 16-bit word. The value is
transferred as whole numbers 0 to±32767 (±200%).
16384 (4000 Hex) corresponds to 100%.
Output frequency has the following format:
0-16384 (4000 Hex) ≅ 0-100% (Parameter 201 Output
frequency low limit-Parameter 202 Output frequency high
limit).
MG27E402
Design Guide
0010 0000 0000 0000 0000
1101 1111 1111 1111 1111
+ 1
1110 0000 0000 0000 0000
Danfoss A/S © Rev. May/2014 All rights reserved.
Example - Status word and current output frequency:
The master receives a status message from the frequency
converter that the current output frequency is 50% of the
output frequency range.
Parameter 201 Output frequency low limit = 0 Hz
Parameter 202 Output frequency high limit = 50 Hz
Status word = 0F03 Hex.
Output frequency = 2000 Hex ⇒ 50% of the frequency
range, corresponding to 25 Hz.
Illustration 4.37 Status Word and Output Frequency
4 4
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