MG.20.B6.02 – VLT is a registered Danfoss trademark
55
VLT
®
2000 Series
Section 1
Section 2
Section 3
Serial data interface (group 5) (continued)
Byte 1:
Start byte which in this case must be the character
< (ASCII: 60).
Byte 2, 3:
The two-digit address of the frequency converter. This
address is also programmed in parameter 500.
Sending to address 00 means broadcasting to all
units connected to the serial port. None of the units
will reply, but they will carry out the command.
Byte 4:
Control parameter telling the VLT frequency converter
what to do with the following data values.
U (update):
Means that the data value (14-18) must be recorded
into the frequency converter.
R (read):
Means that the master wants to read the data value
of the parameter stated in bytes 9-12.
C (control):
Means that the frequency converter only reads the
four command bytes (5-8) and returns with status.
Parameter number and data value will be ignored.
I (read index):
Means that it reads index and parameter and returns
with status. Parameter is stated in bytes 9-12 and in-
dex is stated in bytes 13-18.
Parameters with indexes are read-only parameters.
Action will be taken on the control word.
Byte 5-8:
Control and status words are used to send
commands to the frequency converter and send sta-
tus from the frequency converter to the master.
Byte 9-12:
The parameter number is set in these bytes.
Byte 13:
Used for the sign for the data value in bytes 14-18. All
characters other than "-" are taken as "+".
Byte 14-18:
The data value of the parameter stated in bytes 9-12
is set in these bytes. 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, e.g.
[0]. Use this number instead of the text data value.
Byte 19:
The position of the decimal point in data values stated
in bytes 14-18. The number states the number of
characters after the decimal point. Byte 19 can thus
be 1, 2, 3, 4 or 5.
Example: The number 23.75 is stated as follows:
Byte No.
13
14
15
16
17
18
19
ASCII character
+
2
3
7
5
0
3
If byte 19 is 9 this indicates an unknown parameter.
Byte 20, 21:
Used for summary control. If no control is necessary
cancel the function using ? (ASCII: 63) in the two by-
tes.
Byte 22
:
Stop byte stating the end of the telegram.
The character > is used (ASCII: 62)
The contr
ol possibilities of the VL
T
■