Product Guide
MWS3A-PRM-2CHC,2CHL
Microwave Presence/Absence Detector
Contents
Section Contents Page
1 Dimensional information 1
2 Description and operation 2
3 Wiring & Installation 3
4 Wiring diagram-Normally open relay wiring 4
5 Wiring diagram-Normally closed relay wiring 4
6 Fixing - Flush 4
7 Fixing - Surface 5
8 Head locking 5
9 Time, Lux & Sensitivity adjusters 5
10 Programming 5
11
Detection pattern diagrams
12
Fault finding
13
Specification
14
Part numbers
1. Dimensions
7
8
8
8
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2. Description and Operation
The MWS3A-PRM-2CH (microwave) detector provides automatic control of lighting loads with optional
manual control. It can be used on incandescent, fluorescent and compact fluorescent lighting, and has the
added benefit of being able to connect an external switch. The MWS3A-PRM-2CH detects movement
using a highly sensitive microwave detector. This works by emitting low power microwave signals and
measuring the reflections as the signals bounce off moving objects. The MWS3A-PRM-2CH has a unique
adjustable sensor head that allows the area of detection to be optimised for the application.
The MWS3A-PRM-2CH detector provides two independently controlled output channels that can be used
for a variety of applications:
Occupancy of two independent lighting circuits using a single detector—
e.g. for essential and non-essential supplies (part no. -2CHC) .
Occupancy and lux control of one lighting circuit and just occupancy control of a second circuit—
e.g. where a row of luminaries by a window is lux controlled whilst inner rows are switched on
occupancy only (part no. -2CHL) .
Occupancy and lux control of a lighting circuit and just occupancy control of a ventilation circuit
(part no. -2CHL) .
Occupancy on both lighting circuits, with separate lux control on each circuit (part no. -2CHL). The
DD-LCDHS must be used for setting up lux switching levels on the second circuit.
Please Note:
When controlling two circuits, the circuits must be on the same phase.
Two modes of operation are available:
Presence detection:
When movement is detected the load will automatically turn on. When the area is no longer occupied the
load will automatically switch off after an adjustable time period. If an external switch is connected, this
can override the lights off (after the detection time period has elapsed it will revert to automatic operation).
An integral adjustable photocell allows the lights to be kept off if there is sufficient ambient light.
Absence detection:
The load is manually switched on using an external switch. When the area is no longer occupied the load
will automatically switch off after the adjustable time period has elapsed. Pressing the switch again during
occupancy override the lights off (after the detection time period has elapsed it will revert to automatic
operation).
In both modes of operation a short button press turns the load on whilst a long button press turns the load
off.
An integral infra-red sensor in the unit allows the unit to be programmed using the optional DD-LCDHS
programming handset. This gives complete flexibility over many of the operating parameters. Without the
handset, manual adjustments can be made to the sensitivity, time settings and Channel 1 ―Lux Hold Off‖
using the controls on the side of the sensor housing.
On the ―LUX‖ versions, using the DD-LCDHS programming handset, as well as setting the above
mentioned parameters (sensitivity, time settings and Channel 1 ―Lux Hold Off‖), the adjustable internal
light sensor can also be programmed to switch the lighting off with one or both outputs during occupancy if
the level of light exceeds a second preset level. It can also be used to set the Channel 2 ―Lux Hold Off‖ if
required.
In addition a variant of the product provides a normally closed contact for fail safe operation (/NC). If the
unit fails, the outputs will default to on.
When the unit is first powered up the microwave sensor will always detect immediately regardless of
whether the room is occupied.
The UHS user handset can also be used to change lux levels and override the lights on or off.
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3. Wiring & Installation
1. Wire the products using the diagram overleaf.
2. To switch from more than one position simply wire two or more units in parallel using the Live,
Neutral and Switched Live wires only.
3. The detector should be sited so that the occupants of the room fall inside the detection pattern
shown in section 11.
4. Corridors or aisles: the unit should be placed at the end of the corridor or aisle and the sensor
head should be angled to look down the corridor or aisle.
5. Open plan areas and offices: the unit can be mounted in a corner looking outwards in which
case the sensor head should be angled . Or the unit can be mounted in the centre of the area
with the sensor head flat.
Note that the higher the sensor is installed the shorter the detection range will be.
Sites as far away as possible from any lighting or ventilation equipment.
Do not fix to a vibrating surface.
Do not fix to a suspended luminaire.
Site as far away as possible from the surface of metal objects.
7. Mount using one of the two options overleaf.
8. Use a small screwdriver to set the LUX level adjuster fully clockwise, the time to minimum (fully
anticlockwise) and the sensitivity to maximum (fully clockwise) using the diagram in section 9.
9. Power the unit up—the load should come on immediately.
10. Vacate the room or remain very still and wait for the load to switch off (should take no more than 2
minutes).
11. Check that the load switches on when movement is detected.
12. The LUX thumbwheel determines the ambient light level at which the lights turn on.
13. Select the time using the adjuster, fully clockwise is the maximum.
14. The area of detection can be varied by altering the angle of the sensor head and the sensitivity
adjuster. Note: on maximum sensitivity this unit is extremely sensitive to movement and may
detect through glass, thin walls or partitions. If this causes a problem reduce the sensitivity by
turning the adjuster anticlockwise.
15. Using the UHS or UHS3 infra-red handset: the override on button turns the unit on permanently;
the override off button turns the unit off permanently; the cancel button cancels the overrides.
When an override is selected an LED will flash inside the unit. The UHS handset can also be used
to set the lux levels—see Section 10.3
Absence detection
16. To use absence detection a retractive (momentary) switch must be connected to the switch
terminal shown on the diagram. Note that this will be switching mains voltage.
17. The unit ships with presence detection as default. To change to absence detection, press and
release the external switch 5 times within the first minute of power up. The LED will turn on solid
for 30 seconds to indicate absence mode has been selected.
18. To change back to presence detection, repeat the above procedure—the LED will flash for 30
seconds to indicate presence mode has been selected.
Note: the above adjustments can also be made using the DD-LCDHS handset instead of the manual
adjusters or external switches. See section 10.
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