BACnet Client

In Client mode inSCADA connects to BACnet/IP devices to read and write their object values.

Step 1: creating the connection

The connection’s ip and port are the server’s own local socket — not the target device’s. The target address is given at device level.

Parameter	Default	Range
Protocol	BACnet	—
APDU Timeout (ms)	3000	100 – 60000
Retries	3	0 – 10

Step 2: creating the device

Parameter	Default	Description
Device Instance	—	The device’s instance number (0 – 4194302)
IP	—	The device’s address
Port	47808	The standard BACnet/IP port
Network	—	On a routed device, the far network’s number (1 – 65534)
MAC Address	—	The device’s MAC on that network
Scan Time	—	The polling interval
Scan Type	—	PERIODIC or FIXED_DELAY

Network and MAC go together

A routed device is addressed by the pair network number + MAC, and half of it addresses nobody: a network with no MAC has no station to reach, and a MAC with no network is a MAC on a network this side cannot name. Give both or neither.

A mistyped MAC is refused at the save, not at the first poll.

Step 3: creating frames

A frame groups the objects that are read together.

Parameter	Default	Description
Use Subscription Mode	off	Take values from COV notifications instead of polling

Which frames to put on COV

Points that rarely change — a door state, an alarm contact, an operating mode — suit COV well. On a continuously drifting analogue measurement, COV can produce more traffic than polling. Splitting frames along that line is what makes the difference.

Step 4: creating variables

Parameter	Default	Description
Object Type	—	The object type (0 – 1023)
Object Instance	—	The object’s instance number (0 – 4194303)
Property Id	85	The property to read; 85 is Present_Value
Array Index	—	The element index on an array property
Write Priority	16	The write priority (1 – 16)
Type	—	FLOAT, INTEGER, BOOLEAN or STRING

Typical variables

Variable	Object type	Property	Description
Room temperature	0 (Analog Input)	85	The measured temperature
Setpoint	2 (Analog Value)	85	A writable setting
Fan status	3 (Binary Input)	85	Running / stopped
Fan command	4 (Binary Output)	85	On / off
Operating mode	19 (Multi-state Value)	85	The mode number

Step 5: starting the connection

Start the connection from the Runtime Control Panel. Its status will show “Connected”.

Related

• BACnet overview — objects, properties and priority
• BACnet/IP Server — the server role