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
0010 0000 0000 0000 0000
1' complement
1101 1111 1111 1111 1111
+ 1
2' complement
1110 0000 0000 0000 0000
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
).
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
Programming
Design Guide
MG27E402
Danfoss A/S © Rev. May/2014 All rights reserved.
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