DR-switch
User Guide AP4493
3
Important: Using the Switch Inputs and Logic Outputs
The
DR-switch
provides contact closure switch inputs and open-collector logic outputs. How these are wired to
external equipment is the responsibility of the installer. Specification details are provided here for the
DR-
switch
inputs and outputs. It is important that the installer is suitably qualified and familiar with external control
circuits to be able to work within the capabilities of the unit. Allen & Heath do not assume responsibility for any
damage done to the unit due to incorrect or faulty connection to external equipment.
Planning and Configuring the System
Before starting make sure you have planned how the system is to work. Allocate the switch inputs and logic
outputs and keep a log of their function. The function of each input and output is configured using the Allen &
Heath
WinDR
software. Refer to the help file within the program for instructions.
Connectors and Grounding
Using the Switch Inputs
Pluggable Phoenix type screw terminal
connectors are used for connecting the
external switches and logic to the
DR-switch
.
Mating plugs are provided with the unit.
Make sure the wires ends are carefully stripped
and inserted into the terminals. Tighten the
screws using the correct slotted screwdriver.
To ensure interference-free operation use
shielded cable. Connect the shields to the
chassis ground screw terminals provided next
to each connector. Fit the screws with the
shake proof washers provided.
For operator safety make sure that
wall plates and other control surfaces made
from metal are correctly bonded to ground
(earth).
Strap the metal plate to the local ground at the
wall box. For ground isolation between the
wall plate and equipment rack connect the
cable shield at the
DR-switch
end only.
If a local ground is not available then use the
cable shield to connect the plate to the chassis
of the
DR-switch
unit as shown. This is not
necessary if the wall plate is made of non-
conductive material such as plastic which
insulates it from the operator.
G
METAL WALLPLATE
CHASSIS EARTH
G
METAL WALLPLATE
LOCAL EARTH BOND
SWITCH
SWITCH
4
3
2
1
5
6
7
8
G
G
12 11 10 9
13
14
15
16
G
G
20 19 18 17
21
22
23
24
G
G
INPUTS
2K2
+10V
OPTO
INTERNAL DR-switch CIRCUIT
(1 OF 8 SHOWN)
The input is opto-coupled to isolate the
DR-
switch
from the connected equipment. It is
switched by linking its connector pin to the
ground (‘G’) pin. Use a contact closure such
as a momentary press switch to do this.
The input pin is fed from the in10V
reference supply through a 2k2 ohm resistor.
Around 5mA maximum current flows when
connected to ground. Combined switch and
cable resistance should not exceed 1k ohm for
the switch to activate.
Each 10way connector provides 8 switch
inputs. Either pin 1 or pin 10 ‘G’ may be used
as the common switch ground. One cable can
feed this ground to a bank of switches. Two
are shown in the diagram here. Do not use the
chassis ground screw which is for cable
shielding and safety earthing only.
For reliable operation we recommend the use
of heavy duty sealed switches.
