4
Step1:
From the positive (12V DC) leg of your power supply (preferably a 2A supply), take a wire to the first
terminal (~) on the AccSens Plus unit and bridge it out with the common of relay 1 and also to the
common of relay 2.
Step 2:
From the negative (0V) leg of your power supply, take a wire to the second terminal (~) on the
AccSens Plus unit. At the same time run a wire to the negative side of your alarm, then run another
wire from the negative side of your alarm to the negative of your magnetic lock/electric lock which is
also bridged to the one side of your RTE (Request To Exit) button. A GND also needs to be wired to the
normally closed contact (NC) in your fire alarm panel if you have one installed.
Step 3:
From the NC terminal of relay 1 on the AccSens Plus unit, run a wire to the positive leg of your
magnetic lock (fail-safe), or from the NO terminal if you have an electric strike (fail-secure).
Step 4:
From the NO terminal of relay 2 on the AccSens Plus unit, run a wire to the positive leg of your
Alarm.
Step 5:
The fire alarm and the RTE button are both external inputs. You will need to run a wire from the EXT 1
(inputs) terminal to the vacant terminal on the RTE button. Another wire must then be run from the EXT
2 (inputs) terminal to the other side of the NC contact of your fire alarm panel.
1.5Adding doors to your system
In order to commence adding doors to your AccSens Plus system a RS485 cable needs to be run
along the route of your door locations, for example refer to Fig.01.
The RS485 cable
Twisted pairs: This cable should ideally be a shielded category 5 cable with twisted pairs. The A and B
lines must always be on the same pair ie. A is red and B is red/blue or visa versa.
Shielding: The shield must only be grounded at one end, if the shield is grounded at both ends then a
ground loop may occur which will effect the efficiency of the communication.
Cable length: RS485 can be run over a maximum distance of 1000m, however longer runs are possible
if a quality cable is used and there is no noise along the run. However if your run is less than 100m then
your cable does not need to be shielded.
Topology: RS485 is intended for a single run type application, and teeing off in a star formation should
not be attempted as this could affect the system. Below are some examples of the correct and incorrect
tee off methods.
