Table of Contents
Advertisement
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 variable frequency drive 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
Reference = 2000 Hex
The variable frequency drive 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
Control word = 047F Hex
Reference = E000 Hex
Present output frequency
The value of the variable frequency drive'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)
Output frequency low limit - Par. 202 Output
frequency high limit).
160
Start command.
50% reference.
0010 0000 0000 0000 0000
1101 1111 1111 1111 1111
1110 0000 0000 0000 0000
Start command.
-50% reference.
0-100% (Par. 201
Decentral Solutions
Example - Status word and current output frequency:
The master receives a status message from the variable
frequency drive 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
range, corresponding to 25 Hz.
+ 1
MG.90.F2.22 - VLT is a registered Danfoss trademark
50% of the frequency
Advertisement
Table of Contents
