Duemmegi Contatto ModDMX Instructions Manual

DUEMMEGI

ADDRESS

Contatto

MILANO-ITALY

DMX Gateway

Power supply 24V= ±25% / 50mA

MODDMX

ON

+24V

0V

L1

L2

P

13 14 16 1715

+24V

BUS

0V

L1

L2

1 2 3

A (+)

B (-)

G

DMX

TX

XLR

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ModDMX: DMX gateway

ModDMX module allows to handle, through the Contatto
bus, up to 32 DMX devices. ModDMX module makes pos­sible the communication on the first 64 of 512 DMX chan­nels allowed by this protocol.

ModDMX module can be successfully employed in profes­sional and domestic lighting applications, where systems
communicating by the USITT DMX-512 protocol are used,
as theaters, disco clubs, architectural lighting, etc.

ModDMX module features the following characteristics:
✗ all functions are managed by the module and can be

controlled by any real or virtual input of the system, by
supervisor or by video-terminal

✗ possibility to control the DMX system from one or more

pushbuttons connected to the Contatto bus

✗ up to 64 sceneries are available to realize “real time”

scenes; the sceneries are stored in the non volatile
memory of the module

✗ management of fade times
✗ management of different rooms by the same ModDMX

Contatto

ModDMX

Even if the standard specifies a maximum of 32 devices for
the DMX line, as a good rule do not override a total amount
of 16-20 devices. If the number of devices is higher than
20, use proper line splitters to connect the devices overrid­ing this limit.

The module can manage up to 64 DMX channels, but the
total amount of connected DMX devices may be lower than
64 if the device gets more than one channel. Moreover, the
total amount of connected DMX devices may be anyway
lower than 32. ModDMX module can operate exclusively in
system using MCP XT controller. Up, Down and Single
Command function, with or without one-touch feature, can
be performed by the module from any real or virtual input of
the system (see in the following of this manual); in addition,
it is possible to save and recall the sceneries.

The module features a removable 5-way terminal block for
the connection to the Contatto bus and a fixed 3-way ter­minal block for the DMX line. A green LED near to the bus
terminal block shows that the module is supplied, while a
yellow LED near to the 3-way terminal block shows the
presence of communication on the DMX line. ModDMX is
housed in a standard DIN 3M box for rail mounting.

Note: this manual applies to ModDMX modules equipped by
firmware version 2.2 or higher.

Address programming

ModDMX module takes 1 output address, 1-channel 16-bit.
The address must be assigned by FXPRO programmer. A
white label on the front panel allows the writing of the as­signed address for an immediate visual identification.

Wiring diagram

The following schematic diagram shows the connection to
be made between ModDMX module, the Contatto bus and
the DMX line, using proper cables as described in the re­lated table.

Generally, the DMX devices feature a female XLR 5-way or
3-way connector, therefore in this case the cable of
ModDMX must be properly wired to a male XLR connector
(not provided) according to the specification of the manu­facturer of the device.

The following table provides some suggestions about the
cables to be used for the connections and the related max­imum length.

Connection Suggested cable

Contatto bus

DMX line

4 x 2.5 mmq MAX not shielded,
MAX 1.5Km

2 twisted pairs 2 x AWG22 MIN
(e.g.: Belden 3107A or 9841 or

CEAM CPR6003), MAX 1Km

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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 in­cluded) to the protective earth, because this can inject
some disturbances causing negative effects on the commu­nication.

All DMX devices must be connected in sequential way; ab­solutely avoid star connections. The DMX line must be ter­minated 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-chan­nel 16-bit, inside Contatto bus. The following table de­scribes the meaning of the data field:

Bit Data field at the output address

1
2
3
4
5
6
7
8
9

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 signi­ficant 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.

Value

or

Scenery Number

or

Channel Number

Command Code

DEC HEX Function

0 0x00

1 ÷ 64 0x01 ÷ 0x40

101 0x65

102 0x66

103 0x67

111 0x6F

112 0x70

113 0x71

125 0x7D

126 0x7E

127 0x7F

128 0x80

129 0x81

130 0x82

131 0x83

133 0x85

134 0x86

135 0x87

136 0x88

140 0x8C

255 0xFF

No operation (stop Up/Down and
Single Command)

Select DMX channel on which the
value specified by the low byte has
to be written

Save the current status of the (in­cluded) channels into the scenery
specified by the low byte
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

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

Recall the scenery specified by the
low byte

Disable the DMX flux; the value of
the low byte has not influence

Enable the DMX flux; the value of
the low byte has not influence
Up command without one-touch on
the CH specified by the low byte

Down command without one-touch
on the CH specified by the low byte

Single command without one-touch
on the CH specified by the low byte

No operation (stop Up/Down and
Single Command)

Up command with one-touch on the
CH specified by the low byte

Down command with one-touch on
the CH specified by the low byte

Single command with one-touch on
the CH specified by the low byte

Switch off (write zero) the DMX
channel specified by the low byte
and store the last value

Recall the last stored value on DMX
channel specified by the low byte
(switch on to last value)

Set as DMX minimum level the
value specified by the low byte

Set as DMX maximum level the
value specified by the low byte

Set as ramp time the value specified
by the low byte, according to the
table reported in the following

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 fol­lowing 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.

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Contatto

ModDMX

To send a well defined value to a well defined DMX chan­nel at the pushing of a button connected to an input module
of Contatto bus, supposed to have assigned the address
127 to ModDMX module, the simplest way is to insert in the
program of MCP XT an equation similar to the following:

AO127:1 = P(0x0164)I1.1 & P(0x0100)I1.2 & \

P(0x0200)I1.3 & P(0x02FF)I1.4 & \

P(0x0300)I1.5 & P(0x03FF)I1.6

where I1.1..I1.6 are the inputs connected to pushbut­tons and AO127:1 is the channel 1 of ModDMX module
(supposing 127 as address).

The values loaded by the Preset (P) function at the activa­tion of an input, in the 16-bit hexadecimal format, will be in­terpreted as follows: the high byte shows the DMX channel
on which the value specified by the low byte ha to be
loaded. Therefore, at the activation of the input I1.1 the
value 0x0164 will be sent to the module, corresponding to
load the value 100 (decimal equivalent of 0x64) on the
DMX channel 1. In the same way, at the activation of input

I1.4, the value 255 (0xFF) will be loaded on the DMX

channel 2 DMX, and so on. The values allowed for DMX
channels, as said before, must be in the range 0 to 255,
and the meaning depends on the type of connected DMX
device.

If a 3-channels RGB device is connected, this taking the
first 3 DMX channels, different values loaded on these
channels could allow, for instance, to reproduce 2563 =

16.777.216 colors.
In this same example, to generate a succession of random

colors, the following simple script and equation can be
used, and this shows the potentiality of MCP XT controller
and of ModDMX module. V1 simply generates a “clock” to
recall the script every 1 second.

script 1

trigger = V1

R0 = RANDOM(0)
R0 = R0 & 0X00FF
R0 = R0 | 0x0100

AO127:1 = R0

R0 = RANDOM(0)
R0 = R0 & 0X00FF
R0 = R0 | 0x0200

AO127:1 = R0

R0 = RANDOM(0)
R0 = R0 & 0X00FF
R0 = R0 | 0x0300

AO127:1 = R0

endscript

V1 = TIMER(!V1,5,5)

Up, Down and Single Command functions

These control functions, with one-touch feature, are those
typical of the conventional dimmer modules of the Domino
family and they will be described here in the following.

Up/Down pushbuttons: pushing and holding Up (Down)
button, the brightness increases (decreases) until the max
(min) value is reached. When the brightness has reached
the desired level, release the button to hold it.

Single Command: holding down the button, the brightness
increases until the max value is reached and, after 1
second about, the brightness decreases to the min value,
then it increases again and so on. Release the button at
the desired level to hold it.

When the lamp is ON, a short pulse (one-touch) on any
control button will cause the complete switching OFF.
When the lamp is OFF, a short pulse on any control push­button will cause the switching ON at the last brightness
level.

In the following example, at the pushing of one of the 3 but­tons, the single command code (0x83) will be sent to the
channel specified by the low byte (01, 02 or 03). When re­leasing the button, the stop code (0x80, 0x00 can be also
used) will be sent to the same channel, allowing the mod­ule to understand that the button has been released.

AO127 = P(0x8301)I1.1 & P(0x8001)!I1.1 & \

P(0x8302)I1.2 & P(0x8002)!I1.2 & \

P(0x8303)I1.3 & P(0x8003)!I1.3

To use the Up and Down functions instead of the single
command, simply use the related codes (0x81 and 0x82 re­spectively).

Ramp or fade time

For ramp, or fade time, it is intended the time required to
change a channel value from 0 to 255. The allowed fade
times are in the range 0 to 255; it is possible to set the de­sired fade time according to the following relationship:

Fade Time = Value x 255 x0,01 [seconds]

The fade time is always the same for all the 64 DMX chan­nels; to set it, use the command 140.

The Fade Time is given in seconds. The following table
shows the relationship between some values that can be
written at the output address +1 and the related fade time.

Set value Fade time [sec]

0 0
1 2,55
2
3 7,65

.... ....

255 650,25 (10' and 50” about)

Note 1: it is not possible to set a different fade time for each chan­nel; in other words, the fade time is a global parameter.

Note 2: the regulation through Up, Down and Single Command
uses a fixed ramp time, so it cannot be modified.

5,10

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