Question: How do you select a device object instance number on a Grundfos BACnet CIM 300 card?


Answer: 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 below.

Default Instance Number
By default, the CIM 300 uses a predefined Device Object Instance Number, which is 227XXX where XXX is the BACnet MAC address. This gives an Instance Number range of 227000 to 227127. See section 3.7 Selecting the BACnet MAC address for more information on MAC addresses. Example: The BACnet MAC address is set to 20 via the hexadecimal rotary switches, so the Device Object Instance Number is 227020.

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. See fig. 9 for DIP switch location.

Note: The Present value of custom device object instance number cannot be 4194303, as this is a reserved value.

Selecting the Device Object Name
The property Device_Name is a character string that must be unique inter-network-wide. By default, the name will be constructed as “Grundfos – XXXXXX” where XXXXXX is the current Device Object Instance Number as described in section 3.5 Selecting the Device Object Instance Number.
Example: The Device Object Instance Number is 227001, so the Device Object Name is “Grundfos – 227001”. If a new name is selected, it will be stored in the device and replace the default naming scheme.

To set the BACnet MAC address, use the two hexadecimal rotary switches (SW6 and SW7). The value must be within the range of 0 to 127. An illegal value will result in a MAC address of 0.