SYSTEMP – Installation Operation Manual (IOM SYSTEMP rev.N)

Table Of Contents
80
11.3 CANbus LAN CONNECTION (ACCESSORY)
SySmart
3
microprocessors can be interconnected in a CANbus LAN (Accessory) that allows several units to run so as to opti-
mise the regulation of the air-conditioned rooms.
To create a LAN, simply connect the units from the terminals on it (see wiring diagram for further information). Refer to the
next chapter for connecting the remote terminal.
A Unit 1
B Unit 2
C End unit (max. 12)
D CANbus network input terminals
E CANbus network output termi-
nals
F CANbus network connection
cable
The connection cable is supplied together with the units. If a change is required, the type of cable to be used for the con-
nection must have the following features:
Main features of serial communication cable
Type Data transmission cable
Application EIA RS485 Interface
Shielding Tinned copper braid - Cover at least 65%
Cross-section and number of conductors 2 x 0.35 mm
2
- AWG 22 + 1 x 0.35 mm
2
- AWG 22
Stranding Twisted pairs
Nominal loss (1 MHz) dB/100m 1.64
Maximum DC resistance for conductor at 20°C Ω/km 49
Insulation resistance at 20°C MΩ*km 5000
Mutual capacitance c-c / c-s nF/km 40 - 70
Inductance mH/km 0.7
Impedance Ohm 120 +/- 0.12
Maximum length m 100
Example
11.3.1 CANBUS LOCAL NETWORK TERMINATING RESISTORS
WARNING!
Set micro switches to ON to activate 120 Ω terminating resistor IN THE FIRST (Unit 1) and
LAST UNIT OF THE LOCAL NETWORK.
In order to assure correct serial communication between the units connected in a CANbus network, the network must have
terminating resistors at both ends. SySmart
3
microprocessors and user terminals are tted with suitable micro switches for activating
suitable 120 Ω terminating resistors if set to ON.
Set micro switch CANLT (3) to
ON to activate the 120 Ω ter-
minating resistor
Set micro switch 2 to ON to
activate the 120 Ω terminat-
ing resistor.
A
E
B
F
D
C
E
D
E
D
F