7
3.2 CIM 300 BACnet module
Fig. 3
CIM 300 BACnet module
3.3 Connecting to the BACnet network
A screened, twisted-pair cable must be used.
The ANSI/ASHRAE BACnet standard states that the cable screen
must only be earthed at one end of the segment to prevent earth
fault currents.
3.4 Setting the BACnet transmission speed
The transmission speed must be set correctly before the CIM 300 is
ready to communicate on the BACnet MS/TP network. DIP switches
SW4 and SW5 are used to set the transmission speed.
The default transmission speed is 9600 bits/s, but higher speeds
are recommended for better data throughput. All devices on the
BACnet MS/TP network must communicate at the same
transmission speed.
Fig. 4
BACnet transmission speed settings
3.4.1 DIP switch settings
Available transmission speeds in bits/s: 9600, 19200, 38400 and
76800.
Use DIP switches SW4 and SW5 to select the desired speed.
The default transmission speed is 9600 bit/s, as per the BACnet
MS/TP standard. The transmission speed will be effective
immediately after setting the values of the DIP switch.
3.5 Selecting the Device Object Instance Number
The Device Object Identifier value consists of two components:
• a 10-bit Object Type (bits 22 to 31)
• a 22-bit Instance Number (bits 0 to 21).
Fig. 5
Bit numbers
The Object Type is fixed and determines that it is a Device Object.
The Instance Number is a numeric code that is used to identify the
device. It must be unique inter-network-wide, i.e. on all
interconnected networks.
The CIM 300 offers two different approaches to setting the BACnet
Device Object Instance Number: default and custom, both
described in the following subsections.
TM
04 1
697 0
908
Pos. Designation
Description
1
Plus
BACnet Plus terminal
(RS-485 positive data signal)
2
Minus
BACnet Minus terminal
(RS-485 negative data signal)
3
Ground
BACnet Ground terminal
4
SW1/SW2
On/off switches for termination
resistor
5
SW3/SW4/SW5
Switches for selecting the BACnet
transmission speed and the default
or custom Device Object Instance
Number
6
LED1
Red/green status LED for
BACnet communication
7
LED2
Red/green status LED for internal
communication between the
CIM 300 and the Grundfos booster
8
SW6
Hexadecimal rotary switch for
setting the BACnet MAC address
(four most significant bits)
9
SW7
Hexadecimal rotary switch for
setting the BACnet MAC address
(four least significant bits)
1 2 3
4
5
6
7
8
9
BACnet terminal
Recommended colour
Data signal
Plus
Red
Positive
Minus
Green
Negative
Ground
Grey
Ground
TM
04
1710
0908
Transmission speed
[bits/s]
SW4
SW5
9600
OFF
OFF
19200
OFF
ON
38400
ON
OFF
76800
ON
ON
TM
04
5977
4509
SW4 SW5
31
22
10 bits
22 bits
21
0
Object type
Instance Number
...
