Useful hint
:
Alphatronics can also supply magnetic contacts with built-in EOL resistors!
Zone inputs of the AlphaVision NG control panel and its expansion modules can also be used as a
Key
Switch
input (see screen 1 in the programming, page 34). Also in this case the End of Line resistors are
used. The 10k Ohm resistor is placed over the key contact, the 1k8 resistor is placed in the key’s casing and
the tamper security is also placed in this loop. Opening the key switch’ casing will then result in a tamper
alarm from the key switch. Using the EOL principal will make tampering with the keyswitch much more
difficult. See figure 1 for zone connection on the AlphaVision NG control panel.
Inputs without EOL
It is possible to program each zone to function with EOL or not. In the case you cannot use a zone with the
EOL principal, for instance when you have magnetic contacts that cannot be opened or which are already
installed, you can program the zone as “digital”. When you are using several zones as digital, you can set the
tamper contacts in series with each other, as you can see below:
Figure 4: Wiring detectors without EOL
Use a 39k resistor or not?
In the past 39k resistors were used often in Visonic detectors, placed over the tamper contact. This still is the
case with the EOL plug on boards. With the AlphaVision NG however, this resistor is no longer required.
The 39k resistor was especially used for the AlphaVision 16, to create extra zones. Leaving the 39k resistor
out will have as result that a detection of movement and a tamper alarm AT THE SAME TIME will result in
a tamper alarm only. However, usually this will never happen simultaneously. How can the burglar reach
and open an armed detector without being detected? And if he does find a way to do so, a monitoring station
will always consider a tamper alarm from an armed system as a burglary report and will act is if it was a
burglary report.
0V power/detector loop
All detectors in the AlphaVision NG system are connected with a four-wire cable. Some installers think they
can combine the 0V from the power supply with the 0V from the detector loop. We strongly advise you
NOT to do this! Through the 0V wire of the power runs current, and a voltage drop will occur. The 0V wire
of the detector loop is used to measure resistance. When both connections run through one wire, the used
current influences the resistance measuring. Especially with longer cables this will result in disturbance of
the resistance measuring.
AlphaVision NG installation manual Rev. 2.0 27-08-2003 Blz. 8/101
