I'm using Beckhoff's BK9000 (Ethernet TCP/IP Bus Couplers) with other KL blocks to connect the switch. I'd like to choose the switch which fits this bus coupler, but I noticed that there are two choices for the switch, NPN or PNP.
According to the website,
Many modern PLC input cards can be configured and wired to be either 'sinking' or 'sourcing' although it will usually necessitate all inputs on a particular input card being configured the same.
Which switch should I choose? Is BK9000 a sourcing or sinking device? Or doesn't it matter at all?
I'm sorry if I'm asking a silly question. I tried to find more information and tutorial, but couldn't find the practical explanation (most of them were just about the general explanation of PNP/NPN or sourcing/sinking).
The BK9000 is only the coupler and doesn't determine whether it is sinking or sourcing. It is the KL cards you choose that determine it. You can choose versions of the KL cards that are either sourcing (supplying the positive voltage), such as the KL2408 or sinking, such as the KL2488
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I'm working on a live music visualisation project, where I am using a particle stream to visualise each channel of audio (vocals, guitar, percussion, bass) which are each coming from a looper.
I have the visualisation aspects working - I do envelope tracking in a separate pd instance, send the envelope details via udp to my gem instance, which then uses that to vary the size and colour of multiple particle streams.
The problem I have is that I am trying to set the origin point of each stream, and they are either interacting or they are controlling the origin of a different stream. The part_velocity also seems to be having a similar issue.
Each particle system has it's own gemhead (which I init as say [gemhead 20] so each one is unique), but changing the XYZ for its [part_source 1 point] object seems to affect a stream that's in a different gemhead chain.
I have also moved it off into an abstraction, where I name its head [gemhead $0] and I am having the same issue.
This unanswered thread from years ago shows two other people having the same problem, but no answers.
Here's a portion of my main patch which calls the abstraction:
And this is the abstraction:
Am I missing something simple here, or is there perhaps a bug in that one of the part_xxx objects is not checking which gemhead list it's in? Note that there are other gemheads in the main patch, some have an argument, some don't, but they're doing other stuff.
Oh yeah, and input is welcome on the somewhat dumb-looking way that I'm preserving state here, I've NO idea what the patterns are here, and cannot for the life of me find any good advice on it!
I'm new to SUMO, Veins, OMNET++ and simulations with a bit background of networks. I have successfully setup environment and run veins 4.6 demo application. On google found that unlike RSU, Car modules are added on the fly.
In demo example car nodes send Airframe11p message, i'm not getting where this message is being populated because in TraCIDemo11p.cc methods (onWSA, onWSM, handleSelfMsg, handlePositionUpdate) we are dealing with WSM message types and BaseWaveApplLayer::checkAndTrackPacket methods ensures that message being sent is either BSM, WSM or WSA.
In veins\src\veins\modules\messages AirFrame11p.msg file exists but on finding references of "AirFrame11p" in project, matches are found in AirFrame11p_m.h and AirFrame11p_m.cc only. If demo is not using these files then for what purpose these files are added? and from where simulation gets the annotation of AirFrame11p.
I'm trying to simulate a car accident scenario without RSU using V2V communication, have replaced demo map with mine, generated random routes, now trying to remove RSU from demo application and exploring to send customized messages (including geo location, speed, direction, time etc) to nearby vehicles in specified range e.g. 100 meters using WiFi direct.
If i'm confusing something then please guide me. Thanks.
The short answer: The AirFrame11p message is a lower level message that encapsulates the upper layer messages. Just use the application message type that is appropriate for your application. If you want to replace the physical layer with WiFi direct instead of 11p, and you're starting from scratch, you're probably in for quite a bit of work, since the VEINS PHY implementation is very intricate. If you have an existing implementation of WiFi direct, it may be worth investigating the integration of VEINS' TraCI implementation with that code.
Encapsulation in VEINS
You are correct that the message types at the application layer are more diverse -- these message types (BSM and WSM) are used to encapsulate "application" behavior; it's just not very well visualized in the simulation execution. You can pause the simulation and look (for example) under scheduled events, where the queued packets can be examined visually.
Unlike regular networks, where such messages would be packaged in IP, MAC and PHY encapsulations, VEINS uses the following encapsulation process: BSMs are packaged in MAC frames (80211Pkt), which in turn are encapsulated by AirFrame11p signals. So basically, you should choose the correct message type for your application.
Footnote regarding application behavior:
Technically speaking, these messages would be more correctly placed at the Facilities layer (see e.g. ETSI's spec), since the periodic exchange of messages provides data stored in the facilities layer, which is then used by cITS/VANET applications that run on top. If you need this, look at Artery (as Ventu suggested in the comments).
I have a general question about how to debug in Simpy. Normal debugging tools don't seem to work, since everything is working on the event loop, and you can't step through the code line by line and inspect what exists at any point in time.
Primarily, I'm interested in finding what kinds of processes and callbacks are in existence at a particular time, and how to remove them at the appropriate point. Are there any best practices surrounding debugging in discrete event simulation generally?
I would just use a bunch of print()s.
One thing you might find useful is the specific requests that can be passed to primitives such as resources. For example you can ask a resource how many users it currently has or how big the queue to use the resource is with:
All of these commands can be found in the documentation, here is the resource example: https://simpy.readthedocs.io/en/latest/api_reference/simpy.resources.html
I'm implementing a small PCI driver for academic purposes, and one thing I'm not clear about if we actually have to provide driver.conf? Different materials which I read (including http://blog.csdn.net/hotsolaris/article/details/1763716), say that for PCI the driver config file is optional, however in my case it seems that pci_config_setup() is successful only with driver.conf provided:
name="mydrv" parent="/pci#0,0/pci8086,2e11"
Then I do:
% add_drv -i 'pciXXXX,YY' mydrv
and it adds in the system with no warning or error messages.
So I assume that some properties of a PCI device can't be derived automatically by the system, e.g. parent bus?
I would appreciate if anybody could shed some light on this. Thanks.
If you look at a random selection of very small files under /kernel/drv for actual physical hardware, you'll see that they almost always only contain the line
ddi_forceattach=1;
Pseudo drivers will have a driver.conf(4) file which reflects their parentage in the system. I really recommend reading that manpage, it goes into good detail about what's required here.
I was working on a Simulink model recently and was using Goto and From blocks to keep a very busy system from becoming a twisted mess of wires. I was informed that I was not to use Goto and From blocks as they are considered bad style (at least, according to my employer).
While I hold that wires should be kept connected whenever possible, I believe that Goto and From blocks can significantly improve the readability of a system/subsystem if the model would result in lots of crossed wires otherwise; especially if the blocks can be color-coded (e.g. purple Goto block goes to all the purple From blocks).
I'd supply an image of the subsystem I'm working with, but I'm not sure I can put it on here. The subsystem itself has about 12 subsystem blocks (and possibly more later) within it, each with two bus-type outputs. The first output of each subsystem goes to a Bus Creator block, and the second output of each goes to a second Bus Creator block. Since the subsystem are aligned vertically and the Bus Creators are to the right, this results in many crossed wires. I was using Goto and From blocks to clean up the system.
I can supply an image of a smaller, but similar model that I put together for this question.
For a system with on the order of 12 subsystems, this becomes very busy. I was using Goto and From blocks to connect the subsystems and the Bus Creators without a plethora of crossed wires.
I believe my employer may be carrying the stigma of using goto statements from text-based languages and applying it to Goto/From blocks in Simulink. Generally speaking, is using Goto and From blocks in this way (or any way) considered to be bad style?
The Mathworks Automotive Advisory Board has published some modeling guidelines (PDF) that include usage of Goto/From. The rules they list are:
Do not have subsystems that are floating, i.e. all inputs / output ports are connected via Gotos. One of the great things about Simulink is the ability to determine signal flow with only a cursory visual inspection, do not destroy this by linking everything with Gotos. At least have one feed-forward and one feedback loop between subsystems connected by signal lines.
My personal opinion on feedback signals is that they should all be connected with signal lines, but I'm sure you can come up with cases where drawing all of them clutters the model.
The second guideline is about the scope of the Goto tag; keep the visibility local as much as possible.
I feel setting visibility to scoped is acceptable also as long as you're not using the matching From more than a couple of levels downstream from the Goto. I've yet to come across a legitimate need for a global Goto tag.
So, all Goto usage isn't bad, and you're right that it can improve readability in some cases. That being said, I don't think Gotos are justified for the picture above. I realize it is just an example, but I should point out that if the buses being created are virtual that order of the inputs at the creator doesn't matter, and rearranging Bus Create and Mux block inputs can work wonders for readability.
The problem with the guidelines above are that there's room for bending them, and developers on your team might do just that. Even if everyone is diligent about following them at first, you may run afoul of these guidelines one day, a long time from now, when you redraw that section of the model for refining / adding functionality. Rearranging inputs and outputs can be especially irritating in middle of implementing some cool new feature. That may be the reason your employer chose to impose a blanket ban. It is inconvenient in some cases, but is easier to enforce.