E6581402c
-10-
3.3. Networ k cable c onnecti on
Connect the BACnet network cable to comm unication option as follows.
Title Description
Wire type Shieldedtwisted cable
Characteristic impedance Between 100 and 130 ohm
Distributed impedance betw een
conductors Less than 100pF per meter
Distributed impedance betw een
conductors and shield
Less than 200pF per meter
Foil or braided shields are acceptab le.
Length of an MSTP segment 1200 meters with AWG18 (0.8m m2)
Cable sheath should be peeled off by about 7mm.
For wiring work, use a f lat blade screwdriver wi th a 0.6mm thick and
3.5mm width blade.
Tightening torque for the termi nal block is 0.5Nm.
* Fix a cable so that a communicati on connector may be not taken the weight of w ire.
3.4. Networ k configu ration
Make up the network as follows.
- Transmission/reception signal s (A, B)
Make up the communication path by connec ting all transmission/recep tion data cables.
- Signal common (GND)
GND is the signal common.
- Grounding the shield of cable (SCR )
Connect the all shield lines of networ k cable. The shield shall be grounded at one end only prevent
currents from being created.
- Termination resistor
A termination resistance of 120 ohms p lus or minus 5% shall be connected at each of the two ends
of the segment medium. This option has a term ination resistor, so if use, set up the termination
resistor SW. (Refer to 2.1 Outl ine)
At least one set, and no more than two sets, of netw ork bias resistors shall exist for each segment.
This option has local bias resistors.
Termination
B
A
GND
+5
510
510
Node with network
biasresistors
120
B
A
GND
Nodewithout
biasresistors
B
A
GND
+5
47k
Nodewith local bias resistors
Thisoption board
47k
4.7k 4.7k
Termination
120
SCR
Communication
cable
Communication
cable
SCRSCR
SW4 TERM
N.B.:Do not connect the SCR terminal to the pow er ground of inverters or other uni ts.
Keep the network cables 20cm or mor e separate from the power cables to prevent from
malfunctioning due to electrom agnetic noise.
⿆mm