Contatto
ModDMX
For the DMX connections always use cables specified for
EIA RS485 communication, with 120 ohm impedance and
low coupling capacitance between the cores. Use a twisted
pair for the lines A and B. Do not connect the shield of the
DMX cable; use another pair to connect the G terminal
(ground) of ModDMX and of the various connected
devices. Do not connect any DMX cable (G terminal in-
cluded) to the protective earth, because this can inject
some disturbances causing negative effects on the commu-
nication.
All DMX devices must be connected in sequential way; ab-
solutely avoid star connections. The DMX line must be ter-
minated at its start and at its end by a 120 ohm resistor (not
provided), as recommended by RS 485 specifications.
Bus commands
As said before, ModDMX takes 1 output address, 1-chan-
nel 16-bit, inside
Contatto
bus. The following table de-
scribes the meaning of the data field:
Bit
Data field at the output address
1
Value
or
Scenery Number
or
Channel Number
2
3
4
5
6
7
8
9
Command Code
10
11
12
13
14
15
16
Command Code
Granted that DMX channel are numbered 1 to 64, the same
DMX channels will be managed through the output address
of ModDMX module.
Considering the 16 bits as group of 2 bytes, the most signi-
ficant byte represents the command code to be executed,
while the less significant byte set the value or the scenery
number or the channel number depending on the specific
command to be executed.
The following table lists the allowed command codes.
DEC
HEX
Function
0
0x00
No operation (stop Up/Down and
Single Command)
1
÷
64
0x01
÷
0x40
Select DMX channel on which the
value specified by the low byte has
to be written
101
0x65
Save the current status of the (in-
cluded) channels into the scenery
specified by the low byte
102
0x66
Include the channel specified by the
low byte in the next scenery that will
be saved; if the low byte is 0, then
all channels will be included
103
0x67
Exclude the channel specified by
the low byte in the next scenery that
will be saved; if the low byte is 0,
then all channel will be excluded
111
0x6F
Recall the scenery specified by the
low byte
112
0x70
Disable the DMX flux; the value of
the low byte has not influence
113
0x71
Enable the DMX flux; the value of
the low byte has not influence
125
0x7D
Up command without one-touch on
the CH specified by the low byte
126
0x7E
Down command without one-touch
on the CH specified by the low byte
127
0x7F
Single command without one-touch
on the CH specified by the low byte
128
0x80
No operation (stop Up/Down and
Single Command)
129
0x81
Up command with one-touch on the
CH specified by the low byte
130
0x82
Down command with one-touch on
the CH specified by the low byte
131
0x83
Single command with one-touch on
the CH specified by the low byte
133
0x85
Switch off (write zero) the DMX
channel specified by the low byte
and store the last value
134
0x86
Recall the last stored value on DMX
channel specified by the low byte
(switch on to last value)
135
0x87
Set as DMX minimum level the
value specified by the low byte
136
0x88
Set as DMX maximum level the
value specified by the low byte
140
0x8C
Set as ramp time the value specified
by the low byte, according to the
table reported in the following
255
0xFF
Broadcast command: send to all
DMX channels the value specified
by the low byte
Some of the more used codes will be described in the fol-
lowing of this paragraph.
Writing a value on a channel
For codes 1
÷
64 (write a value on a channel) the allowed
range for the value is 0 to 255, taking in account the type of
the connected DMX device, which can be a RGB spot, a
rotating light machine or others. For this reason, regarding
the meaning of each value, always refer to the manual of
the connected DMX devices.
DUEMMEGI
s.r.l. - Via Longhena, 4 - 20139 MILANO
Tel. 02/57300377 - Fax 02/55213686 –
www.duemmegi.it
Rel.: 2.2 December 2013
Page 2 of 7
HOME AND BUILDING AUTOMATION
