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Help regarding QX Function Block [message #1735500]

Mon, 20 June 2016 08:34

Eclipse User

Hi,

I am new to 4DIAC. I want to develop a system which will communicate with Raspberry Pi. For this I have used the PUB/SUB model and used QX function block. Everything is working fine but the QX function block is not able to receive the data.

PFA the screenshot.

Regards,
Santosh

Attachment: Receiver_embres.png
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Attachment: Application.png
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Attachment: Sender_embres.png
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Attachment: System_Config.png
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Re: Help regarding QX Function Block [message #1735507 is a reply to message #1735500]

Mon, 20 June 2016 09:46

Eclipse User

Hi Santosh,

My first guess would be the IP address you're using in the PUB/SUB blocks are wrong.

192.168.0.8:61499 is the TCP address of your Raspberry Pi that is used to connect to, send blocks and all other mangaing connections, but the the PUB/SUB should use UDP multicast addresses according to http://www.holobloc.com/doc/ita/index.htm

So, try changing the ID parameter of both Publish and Subscriber to, for example, 225.0.0.0:61499 (must be the same for both)

Jose

Re: Help regarding QX Function Block [message #1735522 is a reply to message #1735507]

Mon, 20 June 2016 10:42

Eclipse User

Hi Santosh,

In addition to Jose's comment I also see that there is an issue with the initialization of the QX block. As long as the block is not initialized it will not write to any output.
What happens when you manually trigger the INIT event of the QX block?

Alois

Re: Help regarding QX Function Block [message #1735526 is a reply to message #1735522]

Mon, 20 June 2016 12:12

Eclipse User

Hi,
Thanks for the quick reply.
I changed the IP of PUB and SUB also I manually checked the QX FB and initialised it. But now I am getting the status 'TERMINATED' in the Subscriber FB.
PFA the screenshot.
Regards,
Santosh

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Re: Help regarding QX Function Block [message #1735642 is a reply to message #1735526]

Tue, 21 June 2016 10:40

Eclipse User

This is very strange especially for the subscribe it is rather incomon to get a terminated. I also looked into the code where this is generated and could not get a real good idea on the problem. One reason could be that the RaspberryPI needs a speicall setup for UDP multicast messages as described in this thread: sourceforge.net/p/fordiac/discussion/708249/thread/918eb215/

Maybe this helps.

Re: Help regarding QX Function Block [message #1735681 is a reply to message #1735642]

Tue, 21 June 2016 19:05

Eclipse User

Now the status of the SUBSCRIBE FB is OK. I have checked all the above mentioned setup except for the Route command because I do not have the root privilege. Could you look in to the attached screenshot and suggest any alternate method.

Thanks,
Santosh

Attachment: SUBSCRIBE.png
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[Updated on: Tue, 21 June 2016 19:06] by Moderator

Re: Help regarding QX Function Block [message #1735705 is a reply to message #1735681]

Wed, 22 June 2016 03:21

Eclipse User

You could test at least manually by setting the the input of the QX block of the output is really set (i.e., set the Out value to true and trigger REQ event of QX).

As it shows ok the subscriber should be initialize correctly. You could as next step look with a networksniffer (e.g., Wireshark) if your packet is sent/received on the Pi. If this is the case the only option you have is to set the routing information. I don't know why this is not set per default. All other linux machines I have this is correctly setup.

As a workaround you could go back and try the UDP direct message you had in the beginning. Although the compliance profile demands a UDP multicast address FORTE's implementation should gracefully also handle direct addresses. But I haven't carefully tested this option.

Re: Help regarding QX Function Block [message #1735932 is a reply to message #1735705]

Thu, 23 June 2016 13:23

Eclipse User

I have tested the QX block manually and it is working fine but the RSP event of the SUBSCRIBE FB is not getting any event. It shows 0. Also I tried the UDP direct message but unfortunately it is still showing the same result.

Re: Help regarding QX Function Block [message #1735980 is a reply to message #1735932]

Fri, 24 June 2016 04:11

Eclipse User

hi this is strange because in your first screenshot the direct UDP mesage was working. Did you change anything here? RSP should be 0 for seubscribers. Or batter can be 0. The important event is the IND. Because this one notifies the application on received messages.

Re: Help regarding QX Function Block [message #1735987 is a reply to message #1735980]

Fri, 24 June 2016 04:26

Eclipse User

Really strange that the example doesn't work. One thing to notice is that the RSP event of the SUBSCRIBE is an input event that can be activated only if there's a connection on it (so, it will remain 0 unless you connect as input of another output event and then trigger it, and actually isn't normally used). When a packet arrives, the IND output event is the one counting up and triggering the QX.

Re: Help regarding QX Function Block [message #1735988 is a reply to message #1735987]

Fri, 24 June 2016 04:27

Eclipse User

Sorry for the duplicate information, the page was open but no refreshed

Re: Help regarding QX Function Block [message #1736288 is a reply to message #1735988]

Tue, 28 June 2016 05:27

Eclipse User

Hi,
I tried again by installing 4DIAC in a UNIX machine and I have only considered the Raspberry Pi resource. Now it is working.
Thanks a lot for your help.

Regards,
Santosh

Re: Help regarding QX Function Block [message #1736299 is a reply to message #1736288]

Tue, 28 June 2016 06:22

Eclipse User

Thanks for the update. It could then be that the firewall on your Windows machine was the cause.

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