The GuardPoint Pro / GuardPoint Pro Lite software can then be configured to communicate with the con-
troller via the RS485/USB interface. Fuller details and instructions on this connection can be found on the
datasheet supplied with the interface, or from the Sensor website.
The communication line is particular particularly susceptible to RFI interference. To prevent this, the follow-
ing rules should be considered:
7
Use a Belden 8443 triple-wire cable ("Receive"/"Transmit"/0v) for the RS232 connection, and a
Belden 9841 twisted and shielded pair cable for the RS485 connection.
A good quality cable shield must be used and the shield must be connected to a strong earth.
The shield should be copper rather than aluminium, since the latter provides only partial attenua-
tion.
All communication cable shielding should be connected to only one extremity in order to avoid
the problem of ground loops, whereas the connection for the RS485 wire shield should be carried
out at the level of the concentrator, and the connection for the RS232 wire shield should be car-
ried out at the level of the terminal.
A distance of at least 50cm must separate all connecting cables from high-tension cables, from
cables connected to an electrical power box controlled by the system, or from any cables capable
of generating strong interference (such as cables connected to high-power motors, generators,
wireless telephone, etc.). Since it is often located besides a variety of cables, the external tele-
phone line can also be a source of strong interference.
Extremely high tension produced by lightning bolts can enter the terminals through these lines.
Such tension can reach the level of hundreds of thousands of volts, so it is advisable to use some
form of surge protection.
Important!
- Do not connect the communication cable screen at any point other than at the RS232/RS485 inter-
face end.
- For all TCP/IP connections, Belden 1624P (24AWG, CAT5, shielded Ethernet) cable is recommended.
- For all RS232 connections, Belden 8443 (22AWG, non-twisted) cable is recommended.
- For all RS485 connections, Belden 9841 (24AWG, twisted and shielded pair) cable is recommended.
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