Cim 300 Bacnet Module; Connecting To The Bacnet Network; Setting The Bacnet Transmission Speed; Dip Switch Settings - Grundfos CIU 300 Functional Profile And User Manual

3.2 CIM 300 BACnet module

1 2 3 4
Fig. 3 CIM 300 BACnet module
Pos. Designation
1 Plus
2 Minus
3 Ground
4 SW1/SW2
5 SW3/SW4/SW5
6 LED1
7 LED2
8 SW6
9 SW7
8
9
5 6 7
Description
BACnet Plus terminal
(RS-485 positive data signal)
BACnet Minus terminal
(RS-485 negative data signal)
BACnet Ground terminal
On/off switches for termination
resistor
Switches for selecting the BACnet
transmission speed and the default
or custom Device Object Instance
Number
Red/green status LED for
BACnet communication
Red/green status LED for internal
communication between the
CIM 300 and the Grundfos booster
Hexadecimal rotary switch for
setting the BACnet MAC address
(four most significant bits)
Hexadecimal rotary switch for
setting the BACnet MAC address
(four least significant bits)

3.3 Connecting to the BACnet network

A screened, twisted-pair cable must be used.
BACnet terminal Recommended colour
Plus Red
Minus Green
Ground Grey
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.
SW4 SW5
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.
Transmission speed
[bits/s]
9600
19200
38400
76800
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).
31 22 21
Object type
10 bits
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.
Data signal
Positive
Negative
Ground
SW4 SW5
OFF OFF
OFF ON
ON OFF
ON ON
...
Instance Number
22 bits
0
7