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Redundant Transmission (CP)
The second pair of jumper pins, JP3 and JP4, are used to set the number of consecutive cyclic wake-up times (CP) that are allowed without transmission
of a radio telegram; in such a case a redundant signal is transmitted. Redundant retransmission refers to the transmission of a radio telegram when no
significant input change has taken place since last transmission.
CP can be any number from 1 to 140, depending on how the second pair of jumper pins is set (Figure 6 1).
Examples
£
CW = 100 sec, CP = 10
Redundant transmission takes place every 100 X 10 = 1000 sec. (approx. 16 minutes, when there is no input change)
£
CW = 100 sec, CP = 100
Redundant transmission takes place every 100 X 100 = 10000 sec. (approx. 2 hours and 45 minutes, when there is no input change)
The following performance parameters have been calculated to show the different results (approximate values) according to the different jumper settings.
Wake cycle [s] (CW
Jumper)
Transmit Interval [s] (CP
Jumper)
Operation Time in darkness
[h] when fully charged
Required recharge time [h]
at 200 lux within 24h for
continuous operation
Constant illumination re-
quired [lux] for continuous
operation
1
(No jumper)
1
(No jumper)
0.4
Insufficient lux
Use a battery
Not applicable
1
(No jumper)
7-14
(JP4)
1.4
1
(No jumper)
70-140
(JP3)
1.7
10
(JP2)
1
(No jumper)
4
10
(JP2)
7-14
(JP4)
13
24
200
10
(JP2)
70-140
(JP3)
16
20
170
100
(JP1)
1
(No jumper)
34
10
80
100
(JP1)
7-14
(JP4)
80
4
80
100
(JP1)
70-140
(JP3)
90
4
80
Table 2:
Performance Parameters by Jumper Settings
N.B. The shaded row indicates the factory default jumper setting, which is the recommended jumper setting. For non-factory default jumper settings,
check with local regulations for compliance with radio-spectrum use requirements.
Transmission Range
The main factors that influence the system transmission range are type and location of the antennas of the receiver and the transmitter, type of terrain
and degree of obstruction of the link path, sources of interference affecting the receiver, and “dead” spots caused by signal reflections from nearby con-
ductive objects. Since the expected transmission range strongly depends on this system conditions, range tests should categorically be performed before
notification of a particular range that will be attainable by a certain application.
Radio signals are electromagnetic waves; hence the further they travel, the weaker the signal becomes and the range is limited. The coverage is further
decreased by specific materials found in the direction of the transmission. For example, while radio waves can penetrate a wall, they are dampened
more than if the waves were on a direct line-of-sight (LoS) path.
The following table shows the different types of walls and range reduction:
Material
Range Reduction vs. LoS
Wood, drywall, glass (uncoated, without metal)
0 – 10%
Brick, particle board
5 – 35%
Metal, ferro concrete, mirrors
10 – 90%
Metallic obstructions such as wall reinforcements, machinery, metal office furniture (large filing cabinets), etc. are major sources of field strength reduc-
tion, but small metal studs on a gypsum dry wall do not show a recognizable screening. Furthermore, fire-safety walls, elevator shafts, stairwells, and
supply areas should be considered as complete transmission screens. In addition, the angle with which the transmission travels through the obstructions
has a major influence on the field strength. The steeper the angle through an obstruction the more the field strength dampens. Therefore, it is preferable
that the transmission should be arranged so that it travels straight and perpendicularly through the obstruction. Wall niches should be avoided as well.
Other factors that restrict transmission range include:
Important objects and factors that decrease or constrain coverage:
£
Metal separation walls or hollow lightweight walls filled with insulating wool on metal foil
£
Inserted ceiling with panels made of metal or carbon fiber
£
Steel furniture, glass with metal coating (typically not used indoor)
£
Switch mounted on metal surfaces (typically 30% loss of range)
£
Metallic switch frames (typically 30% loss of range)
