Present Output Frequency - Danfoss VLT 2800 Series Operating Instructions Manual

It is possible to change the direction of rotation via
the serial reference. This is done by converting the
binary reference value to 2's complement.
See example.
Example - control word and serial communication ref.:
The frequency converter must 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 the
first complement; then 1 binary is added to
get 2's complement:
2000 Hex =
´ 1 komplement =
´ 2 komplement =
Control word =
Reference =
å Present output frequency
The value of the present output frequency of the
frequency converter at any given time is transmitted
26
VLT® Serie 2800 and VLT® Serie 6000 Modbus RTU
0010 0000 0000 0000 binary
1101 1111 1111 1111 binary
+ 1 binary
1110 0000 0000 0000 binary
047F Hex. Start command
E000 Hex. -50 % reference
as a 16-bit word. The value is transmitted in the form
of whole numbers 0 - ±32767 (±200 %).
16384 (4000 Hex) corresponds to 100 %.
The 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 present output frequency:
and present output frequency: The master receives
a status message from the frequency converter
saying that the present output frequency is 50
% of the output frequency range.
Par. 201 Output
frequency low limit =
Par. 202 Output
frequency high limit =
Status word =
Output frequency =
MG.10.S1.22 - VLT is a registered Danfoss trademark
0 Hz
50 Hz
0F03 Hex. Status
message
2000 Hex. 50 % of
the frequency range,
corresponding to 25 Hz.