Grundfos CIM 300 - Connecting to the Bacnet Network; Setting the Bacnet Transmission Speed; Selecting the Device Object Instance Number

2.3 Connecting to the BACnet network
Use a screened, twisted-pair cable.
BACnet terminal Recommended colour Data signal
Plus Red Positive
Minus Green Negative
Ground Grey Ground
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.
2.4 Setting the BACnet transmission speed
Set the transmission speed correctly before CIM 300 is ready to
communicate on the BACnet MS/TP network. Use DIP switches
SW4 and SW5 to set the transmission speed.
The default transmission speed is 9600 bit/s, but we recommend
higher speeds for better data throughput. All devices on the BACnet
MS/TP network must communicate at the same transmission
speed.
SW4
SW5
TM041710
BACnet transmission speed settings
2.4.1 DIP switch settings
Available transmission speeds in bit/s: 9600, 19200, 38400 and
76800.
Use DIP switches SW4 and SW5 to select the desired speed.
Transmission speed
[bit/s]
SW4 SW5
9600 OFF OFF
19200 OFF ON
38400 ON OFF
76800 ON ON
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.
2.5 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
10 bits 22 bits
21 0
Object type Instance Number
...
TM045977
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.
CIM 300 offers two different approaches to setting the BACnet
Device Object Instance Number: default and custom, both
described in the following subsections.
2.5.1 Default Instance Number
By default, CIM 300 uses a pre-defined Device Object Instance
Number, which is 227XXX where XXX is the BACnet MAC address.
This gives an Instance Number range of 227000 to 227127.
Example
The BACnet MAC address is set to 20 via the hexadecimal rotary
switches, so the Device Object Instance Number is 227020.
Related information
2.7 Selecting the BACnet MAC address
2.5.2
Custom Instance Number
To use the complete Instance Number range, set the new Instance
Number with the BACnet object Custom Device Object Instance
Number (AV, 0), and set SW3 to ON. This will immediately set the
new Device Object Instance Number.
SW3
TM041709
Device Object Instance Number
Device Object Instance Number SW3
Default (227000 + BACnet MAC address) OFF
Custom, set with object (AV, 0) ON
The default Present_Value of the Custom Device Object Instance
Number is 231.
Example
The Present_Value of the Custom Device Object Instance Number
(AV, 0) is 231, so the Device Object Instance Number is 231.
The Present_Value of the Custom Device Object Instance
Number cannot be 4194303, as this is a reserved value.
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English (GB)