Setting The Radiator Delay Switches; System With One Transmitter; Determining Delay Switch Positions By Measuring The Cable Lengths - Bosch INTEGRUS Installation And Operating Manual

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1.5 Setting the radiator delay switches

As described in section 1.3.6, differences in the delays of the signals picked up by the receiver from two or more radiators can
cause black spots as a result of the multi path effect.
The signals picked up by the receiver are delayed by:
N
the transmission from transmitter to radiator through the cable (cable signal delay)
N
the transmission from radiator to receiver through the air (radiation signal delay)
N
for systems with two or more transmitters: the transmission through the slave transmitter(s)
To compensate the signal delay differences, the delay of each radiator can be increased. These signal delays can be set with the
delay switches at the back of the radiator.
The cable signal delays can be determined in the following two ways:
N
by measuring the cable lengths
N
by measuring the impulse response time with a delay measurement tool
In both cases the cable signal delays can be calculated manually and with the delay switch calculation tool (available on the
documentation CD-ROM).
For systems with one transmitter and radiators directly connected to the transmitter with equal cable lengths, it is not necessary
to calculate the cable signal delays. In that case set the delay switches on all radiators to zero and determine whether to
compensate for radiation signal delay (see section 1.5.3)
The next sections describe how to calculate the delay switch positions manually for systems with one transmitter, or two or
more transmitters.
See the delay switch calculation tool for the procedures how to calculate the delay switch positions automatically.
: The delay switch calculation tool eases the calculation of the delay switch positions.
1.5.1

System with one transmitter

1.5.1.1

Determining delay switch positions by measuring the cable lengths

Use the following procedure to determine the delay switch position based on cable lengths:
1. Look up the cable signal delay per meter of the used cable. The manufacturer specifies this factor.
2. Measure the lengths of the cables between the transmitter and each radiator.
3. Multiply the lengths of the cables between the transmitter and each radiator with the cable signal delay per meter. These are
the cable signal delays for each radiator.
4. Determine the maximum signal delay.
5. Calculate for each radiator the signal delay difference with the maximum signal delay.
6. Divide the signal delay difference by 33. The rounded off figure is the signal delay switch position for that radiator.
7. Add delay switch positions for radiators under a balcony, if applicable (see section 1.5.3)
8. Set the delay switches to the calculated switch positions.
: Turn the delay switches carefully to a new position until you feel that it clicks into position, to prevent that a switch is positioned
between two numbers, which would result in a wrong delay setting.
For systems with a cable length difference of more than 50 meters, it is recommended to use a measurement tool to determine the delay
differences in order to calculate the delay switch positions..
Figure 1.26 and Table 1.1 illustrate the calculation of the cable signal delay.
BOSCH Security Systems B.V.| February 2003
INTEGRUS | Digital Infra-red Language Distribution System