How to send response to ReadPropertyRequest

[dinesh4761]

Hi,

First of all thanks for BACnet4J. Nice BACnet Stack.

I am developing code which simulates some BACnet device and I need to
send reply to "[size=18]ReadPropertyReqest[/size]".
Wherein Present Value of BACnet object mentioned.

Does anyone know about it? If yes please help me.

Regards,

Dinesh

[dinesh4761]

Hi,

I think it should be "ReadPropertyAck". Because, from VTS I sent this request then I found following in Wireshark.

No. Time Source Destination Protocol Length Info
1435 498.012518 192.168.0.103 192.168.0.1 BACnet-APDU 67 Complex-ACK readProperty[ 1] analog-input,0 present-value

Frame 1435: 67 bytes on wire (536 bits), 67 bytes captured (536 bits)
Ethernet II, Src: CompalIn_b2:45:7e (00:26:22:b2:45:7e), Dst: Teracom_6b:4d:e0 (00:26:15:6b:4d:e0)
Internet Protocol Version 4, Src: 192.168.0.103 (192.168.0.103), Dst: 192.168.0.1 (192.168.0.1)
User Datagram Protocol, Src Port: bacnet (47808), Dst Port: bacnet (47808)
BACnet Virtual Link Control
Building Automation and Control Network NPDU
Building Automation and Control Network APDU
0011 .... = APDU Type: Complex-ACK (3)
.... 0000 = PDU Flags: 0x00
Invoke ID: 1
Service Choice: readProperty (12)
ObjectIdentifier: analog-input, 0
Property Identifier: present-value (85)
property Array Index (Unsigned) 1
{[3]
present-value: 23.000000 (Real)
}[3]

And it is quite similar as mentioned in one of the PDF of BACnet Standard which I found on Internet.

But still I don't know how to send "ReadPropertyAck".
If someone is knowing please help me.

Thanks.

[dinesh4761]

Hi,

I got following.

    ReadPropertyRequest rprr = new ReadPropertyRequest(localDevice.getNextInstanceObjectIdentifier(ObjectType.analogInput), PropertyIdentifier.presentValue, null);

    ReadPropertyAck unRS = new ReadPropertyAck(localDevice.getNextInstanceObjectIdentifier(ObjectType.analogInput), PropertyIdentifier.presentValue, null, rprr);

    InetSocketAddress addr = new InetSocketAddress(InetAddress.getByName("192.168.0.255"), 47808);
    
    ComplexACK ack = new ComplexACK(true, true, by, by, by, unRS);

Is it correct?

If yes then how to send this Complex Request Ack?

Please reply,

Thanks in advance.

[dinesh4761]

Hi,

Greetings!

I got the answer and I am too much happy about it.

Because, I just run Slave device test program and then
send the "ReadPropertyRequest" from the another PC using
VTS. And then monitored acctivities going on in Wireshark.

I found the reply as ComplexAck by Slave device test program.

Thank you so much serotonin for developing such genius API.

But, now I am moving ahead.
That is I am implementing COV (Change of Value) functionality.

So I want some help on the same.
If anybody is knowing the same please let me know.

Regards,

Dinesh

[ThomasRobinson]

This is very important information Dinesh..Good one.

[dinesh4761]

Thanks Thomas for compliments.