79
MG.30.A7.02 - VLT
®
is a registered Danfoss trademark
Bit
15
14
13
12
11
10
09
08
07
06
05
04
03
02
01
00
0/1
0
0
0
0
1
0
1
1
1
0
0
0
0
1
1
1
ASCII
@
K
H
G
Communication example:
A VLT
®
frequency converter with address 1
is to have a start signal and speed refer-
ence equivalent to 40 Hz. A start signal is
given with the help of the control word (see
example on
p
. 77), and the speed refer-
ence is written to parameter 516, bus
reference, 80% equivalent to 40 Hz, the
maximum frequency being 50 Hz. This
gives the following telegram structure:
Telegram from master (PC or PLC) to frequency converter
Function
Byte no.
ASCII character
Decimal value
Start byte
1
<
60
2
0
48
3
1
49
Control character
4
U
85
5
O
79
6
G
71
7
D
68
8
@
64
9
0
48
10
5
53
11
1
49
12
6
54
Sign
13
+
43
14
0
48
15
0
48
16
0
48
17
8
56
18
0
48
Comma
19
0
48
20
0
48
21
7
55
Stop byte
22
>
62
Data value
Check sum
Check sum: Byte 2-19 = 1007 reduced to 07
Address
Control/status word
Parameter no.
Groups
Bit 15, Timers OK/above limit:
Bit 15 = “0” means that the timers for
respectively thermal motor protection
(described on p. 130) and thermal VLT
®
protection have not exceeded 100%. Bit 15
= “1” means that one of the timers has
exceeded 100%.
Example:
The status word below states that the
motor is running at the required speed
reference but outside the defined fre-
quency range and therefore bit 10 = “0”
(out of frequency range) and bit 07 = “1”
(warning). Voltage, current and timers are
OK.
Serial data interface,
group 5..
(continued)
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