CIPer
TM
MODEL 50 CONTROLLER
–
INSTALLATION AND COMMISSIONING INSTRUCTIONS
55
31-00233-02
BACnet MS/TP Bus Connection
The CIPer Model 50 controller features two RS485 interfaces to which BACnet MS/TP devices can be
connected: RS485-1 (consisting of push-in terminals 24 [GND-1], 25, and 26) and/or RS485-2 (consisting
of push-in terminals 29, 30, and 31 [GND-2]).
NOTE
GND-2 is internally connected with 24V-0 (terminal 1)
BACnet MS/TP Bus Considerations
•
RS485-1 (isolated)
–
Max. BACnet MS/TP bus length: 3600 feet (9.6
–
78.8 kbps) or 2400 feet (115.2 kbps) (see also
section "RS485 Standard" ).
–
Use only shielded, twisted-pair cable and daisy-chain topology.
–
Must conform to EIA-RS485 cabling guidelines (see section "EIA 485 Cable Specifications").
•
RS485-2 (non-isolated)
–
Max. BACnet MS/TP bus length: 3600 feet (9.6
–
78.8 kbps) or 2400 feet (115.2 kbps) (see also
section "RS485 Standard" ).
–
Use only shielded, twisted-pair cable and daisy-chain topology.
–
Ground noise should not exceed the EIA-485 common mode voltage limit.
–
Must conform to EIA-RS485 cabling guidelines.
–
Should not extend beyond a single building.
Connecting CIPer Model 50 via RS485-1 Interface to a BACnet MS/TP Bus
NOTE
For Figure 45a and Figure 47, please note the following:
•
Always power each CIPer Model 50 controller and the connected BACnet MS/TP modules
via separate transformers.
•
For "L," see section "RS485 Standard
•
If any of the devices are electrically isolated, it is recommended that those devices be
connected to signal ground. See section "RS485 Standard".
Example 1: Single CIPer Model 50 Controller and Connected BACnet Modules (with inserted termination
resistor)
Figure 45; Connection of a single CIPer Model 50 controller via its RS485-1 interface to a BACnet MS/TP
Bus
The termination resistor must be inserted directly into the terminals of the last BACnet MS/TP module.