ComAp Inteli Mains NT BaseBox, Communications Manual

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IGS-NT Communication Guide
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Note: For CAN bus extension is possible to use I-CR module. It allows extension of CAN to more segments
with next 200m adition length. for more information see I-CR Module for CAN Bus Extension on page 67 .
6.1.4 RS485 connection
External units can be connected on the RS485 line in any order, but keeping line arrangement (no tails, no star)
is necessary.
Standard maximum line length is 1000m.
Shielded cable has to be used, shielding has to be connected to PE on one side (controller side).
RS485 bus line has to be terminated by 120 ohm resistors on the both ends. Always check the number and
placement of terminating resistors in the RS485 bus line, only correct wiring ensures reliable operation!
Resistors must be placed at either end of the line (see picture), and correct number of resistors must be used!
Correct number can be checked using ohmmeter - when power supply for ALL devices on the RS485 bus line is
switched off, the resistance measured between A and B wire should be 60 Ohms. For longer distances is
recommended to connect RS485 COM terminals between all controllers and cable shielding to the ground in one
point. External units can be connected on the RS485 bus line in any order, but line arrangement (no tails no star)
is necessary.
Availability of embedded galavanic separation of RS485 port in ComAp products
All InteliGen controllers - port RS485(1) NO
All InteliSys controllers - port RS485(1) NO
All InteliGen controllers - port RS485(2) YES
All InteliSys controllers - port RS485(2) YES
IG-Display, IS-Display - port RS485 YES
InteliVision 8 - port RS485, CAN YES
InteliVision 5 - port RS485 NO
InteliVision 5 RD - port RS485 YES
InteliVision 5 CAN - port CAN YES
InteliVision 12Touch - port RS485, CAN YES