BACnet IP - Instance & item setup
How to setup a BACnet IP instance and item in SIA
Parameters
When using the BACnet IP Connector both the instance and item have specific parameters. These parameters are required as they are needed to establish connection and to identify which memory to read from.
Instance
The instance needs the following parameters to establish a connection to the PLC:
| Parameter | Description |
|---|---|
| Address | The BACnet Device Instance Number (not the IP address) |
| Network Interface |
Which ethernet port on SIA is the device connected to |
| Device Id |
The Device ID that the SIA unit should have, leaving it to zero will use a default value. |
Info
See Wiring & peripherals article to find the correspondence between SIA port X1/X2 and eth0/1
Item
The item parameters that is needed to read the tags in the PLC memory:
| Parameter | Description |
|---|---|
| Object Type |
What type is being targeted (see below) |
| Object Instance |
Object Instance address |
| Property |
What property of the object should be exposed (see below) |
| Data type |
What is the type of the property data (see below) |
Data types
The following table shows how to address the various types of data types.
| Data type | Description |
|---|---|
| Boolean |
0 or 1 |
| Unsigned int |
A 32 bit unsigned integer |
| Signed int |
A 32 bit signed integer |
| Real |
A 32 bit floating point representation |
| Double |
A 64 bit floating point representation |
| Enumerated |
An enumeration |
| Octet string |
A string of bytes |
| String |
A string of chars |
Properties
Currently the following properties of objects are supported
| Propety |
Description |
|---|---|
| Present value |
The current value of the object |
| Description |
The description of the object |
| Object name |
The name of the object |
| Object type |
The type of the object |
| Object identifier |
The identifier of the object |
| Out of service |
Boolean value of the out-of-service state of the object |
Object types
Currently the following object types are available
| Object type |
BACnet number |
Description |
|---|---|---|
| Analog input |
0 |
Analog input |
| Analog output |
1 |
Analog output |
| Analog value |
2 |
Analog value |
| Binary input |
3 |
Binary input |
| Binary output |
4 |
Binary output |
| Binary value |
5 |
Binary value |
| Large analog value |
46 |
Double precision Analog value |
| Integer value |
45 |
Integer |
| Positive integer value |
48 |
Positive integer |
| Octet string value |
47 |
Array of bytes |
| Character string value |
40 |
Array of chars |