VLT
®
FCD Series
Programming, FCD
300
It is possible to change the direction of rotation via the
serial reference. This is done by converting the binary
reference value to 2
’
complement. See example.
Example - Control word and serial communication ref.:
The frequency converter is to receive a start
command and the reference is to be set to 50%
(2000 Hex) of the reference range.
Control word = 047F Hex
⇒
Start command.
Reference = 2000 Hex
⇒
50% 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
Control word = 047F Hex
⇒
Start command.
Reference = E000 Hex
⇒
-50% reference.
■
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 - ±32767 (±200%).
16384 (4000 Hex) corresponds to 100%.
Output frequency has the following format:
0-16384 (4000 Hex)
0-100% (Par. 201
Output frequency low limit
- Par. 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.
Par. 201
Output frequency low limit
= 0 Hz
Par. 202
Output frequency high limit
= 50 Hz
Status word = 0F03 Hex.
Output frequency = 2000 Hex
⇒
50% of the
frequency range, corresponding to 25 Hz.
MG.04.B7.02 - VLT is a registered Danfoss trademark
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