35
VLT
®
Series 2000
Programming
Byte 1:
Start byte, which in this case must be the character
"<" (ASCII: 60).
Byte 2 and 3:
The two-digit address of the adjustable frequency drive.
This address is also programmed in parameter 500.
Sending to address 00 means transmission to all units
connected to the bus. None of the units will reply, but they
will carry out the command.
Byte 4:
Control parameter telling the drive what to do with the
following data values.
U (update)
Means that the data value, bytes (14-18), must be read into
the drive.
R (read)
Means that the master wishes to read the data value of the
parameter in bytes 9 through 12.
C (control)
Means that the drive reads only the four command bytes, 5
through 8, and returns with status. Parameter number and
data value are ignored.
I (read index)
Means that the drive reads the index and parameter and
returns with status. The parameter is stated in bytes 9
through 12 and index is stated in bytes 13 through 18.
Parameters with indices are read-only parameters. Action
will be taken on the control word.
Byte 5 through 8:
Control and status words, used to send commands to the
frequency converter and to send status from the frequency
converter to the master.
Byte 9 through 12:
The parameter number is inserted in these bytes.
Byte 13:
Used for the sign before data value in bytes 14 through 18.
All characters other than “-” are taken as “+”.
Byte 14 through 18:
Here is placed the data value of the parameter stated in
bytes 9 through 12. The value must be a whole number. If a
decimal point is needed, it is stated in byte 19.
NOTE:
Some data values have brackets with a number, for
example “[0]”. Use this number instead of the “Text”
data value.
Byte 19:
The position of the decimal point in the data value stated in
bytes 14-18. The number states the number of characters
after the decimal point. Consequently, byte 19 can be 0, 1,
2, 3, 4 or 5. For example, the number 23.75 is stated:
Byte no.
13 14 15 16 17 18 19
in ASCII character
+
2
3
7
5
0
3
If byte 19 = 9, this indicates an unknown parameter.
Byte 20 and 21:
Used for summary control. If there is to be no control, the
function can be cancelled by means of the “?” character
(ASCII: 63) in the two bytes.
Byte 22:
Stop byte, stating the end of the telegram. The character
“>” is used (ASCII: 62).
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