ShaunR

Thanks! It is an alternative solution to "events", but it works well.

It will work WITH events as well Look at what it is doing rather than how it is implemented.

If it can be made in LV, this does not mean it should be made in LV.

If it can be made with something else, this does indeed mean that it should.

And - use LV exclusively for what it was ment to be used for , namely DAQ.

Use the right tool for the job!

I sure hope your finger pointin' is limited to your own direction there buddy!

“It's not whether you win or lose, it's how you place the blame.” : Oscar Wilde

I don't know that I'd be exposing images of my torrents folder to the general public. Errr, that is if I had one...

lol. Luckily I don't live in the USA. so am not paranoid. But now you have pointed it out in text, I know who to blame when it turns up of a search engine eh?

Anyhoo, programmers have to install these nefarious clients so they can come up with software to defeat them....right? Your virus scanner would go ape on one of my machines.

Nope.

But I can get them above if i do Dir /on.

I'm aware of that, but they're "phantom" in the sense that they shouldn't be returned by the List Folders operation (and aren't, except on network shares). That's the issue.

Well.

This is what I get when I follow your instructions.

LV2009, Windows 7, LS-CHL NAS storage (don't know the versions off-hand but know its Samba on Linux).

They are not phantom directories. They are shorthand for the current directory and the parent directory.

Filenames, Paths and Namespaces

If you type in "cd .." in a command prompt it will take you to the parent directory.

If you allow "view hidden files" and "OS Files" and uncheck "Hide Known File Types"in the folder options you will also see them on the local drive.Its a throwback to DOS.

I test the network functionality of the embedded firmware for the various bar code and labeling printers my company makes. As for asking the admin for an IP address I am the admin and I manage a test network with 25 VLANs, multiple switches, multiple wireless access points and every possible WiFi security. When testing network securities every security is assigned to its own VLAN (subnet) and when testing securities you are not guaranteed the same address each time you test a given printer. We have too many devices to statically assign all the addresses. In addition, the major problem that we have is that individual printers can run different types of firmware. When a printer is switched from one type of firmware (generally a different printer control language) to another its network settings are defaulted and which can mean it switches in normal network security to the default of no security resulting in a new IP address. I am trying to write an utility that would scrub the network for these printers that changed and reconfigure them to their properly assigned network security. These printers are part of a lab that runs long term network stability tests. Manually reconfiguring every printer is very time consuming and a pain in the butt.

Since I am the admin I am actually looking at the possibility of querying the network switches for this information. I was hoping to avoid this if possible. However that is the path that I am currently investigating.

Side note: The printers do support a broadcast query to identify themselves on the network however there are issues with having this work reliably across subnets, at least when doing the query as a broadcast. Broadcast UDP traffic is not routed across subnets.

Hmmmm. Knarley one. Surprised there's no DNS in that lot though. It'd be easy then.

Personally I would try and get a change in the next firmware update (dip switch or special dongle) that means it remembers its last set IP address regardless of re-flashing (if set) or defaults (if not set). Then its not your problem...lol. We do it with things like baud rates and startup modes. Design for test is the motto. You can set it up on the bench and then put it where you like and forget about it.

But I'm guessing thats not an option (I'm very lucky in having very flexible engineers and managers that I can bully ). So I'll have a sleep on it and see if I can think of anything else.

THis only works if the PC has communicated with the device. In the situation I am working the devices will not only be changing their IP addresses but also changing subnets as well. The local ARP tables will not work since the IP address is required to build the ARP table. The ARP protocol is used to obtain the MAC address when you have the IP Address or the device. Unfortunately it is not designed to work the other way. Besides, there is no way in LabVIEW to force an ARP packet to be sent and receive the reply.

Indeed. The MAC address is a physical assignement (serial number if you like) and the IP address is a logical (arbitrary) assignment by the co-ordinator-usually a DNS server or router. The only thing that knows about the mapping is usually the router (s), or (as you rightly say) the local PC if it has communicated with the device. You can force an update to an ARP cache by pinging, but, the pitfall here though (apart from having to know the IP address first) is that if the ARP cache is on a router, its the routers cache that gets updated not your local one.

What you are trying to do is a bit like knowing someones name and trying to get their house address. You can look them up on the "Electrol Role", but you only have access to your own countrys electral role and they could be anywhere in the world. If they (or you) have already exchanged letters then you have thier address.

I think you will find this a dead end since it could circumvent security. What is it you are trying to do that you have MAC addresses but not IP addresses? Wouldn't it be easier to ask the Admin for the IP address the device has been assigned?

if you are running windows then you can go to a command prompt and type in "arp -a".

It will give you the IP to MAC mapping that your PC knows about.

Yes I meant for sure Full Duplex and the USB Bus is able to do that. So if you have an USB to RS-485 interface with 4 wire output (I think it is an oxymoron since RS-485 usually implies 4 wire connection), then there should be no problem in having real Full Duplex operation. The converter will need a little intelligence and buffer to store packets as they are transmitted over the USB bus back and forth, but for the normal observer it will look like real Full Duplex.

Bi directional as you seem to define it here makes of course little sense in such a setup.

Rolf Kalbermatter

Well. The difference may at first glance seem semantics. But it is fundamentally important. Whilst "Bi-directional" literally means "2-way", Full duplex means "2-ways simultaneously"!.

If you think of the difference between a walkie talkie and a telephone. One you cannot hear the person at the same time as you are speaking, the other you can. But they are both bi-directional.

Its much harder having an arguement on a walkie talkie than a phone...lol.

I wouldn't agree that RS485 implies 4 wires. (RS422 yes but not RS485). Almost all modern industrial PC's come with at least 1 COM port that is configurable to RS232, RS422 and RS485. Only when configured to RS422 does it use 4 wires. RS485 they use only 2.

The good thing is though, that RS485 works with RS422 but not the other way round So if you set the PC to RS422 you get true full duplex operation and can talk to RS485 devices. The penalty is that the bus cannot support as many devices.

I think we will have to wait for USB 3.0 for true full duplex USB

Hi all ,

I have installed the LabVIEW 8.6 and IMAQ Vision 7.1, the installations of both were fine. I can use the Vision assistance normally, but for the LabVIEW it has a problem. In the diagram, I can not find ant module in the item of Vision amd Motion. Is there any thing wrong that need to be fixed ? Can anyone has the experience in this problem ?

Thanks in advance.

You also need to install the Vision Development Toolkit. And the Motion Control Toolkit which are installed separately.

It makes more sense to me when you select this relay module. There is one thing I haven't tell you that I need to measure three tanks like this, so I need 3x3 = 9 channels.

NI 9485 x 2

Excellent "cat skinning" there Shaun! You absolutely shreaded the "box" I was thinking in.

Ben

I have my moments. As few and far between as they may be though

Cheers, but its not that I want to load it, I just want to know when the VI tests itself - is it the "active VI" in the subpanel out of a possible number of VIs at a given time. So if it isn't I don't want any actions to be performed, so unfortunately this will not work for my task. Thanks tho.

<edit>

Ok had a thought and it worked

The Front Panel:Open property is True when the VI is loaded in the subpanel

False otherwise

Easy!

Problem sorted

Cheers

</edit>

Ah. Thought you wanted to definitively know. Just for reference. It will also show as maximized.

Is there a way for a VI to tell if it is currently loaded in a subpanel?

Maybe a property?

Anyone know?

Cheers

JG

Not sure if there is a better way. But if you try to load it into a sub-panel and it is already in one, you will get

Error 1145

Possible Reason(s)

Labview: Cannot open VI because it is already in a subpanel control.

If its not in memory, it will succeed, and if its already running but not in a sub panel you get

Error 1144

LAbview: Cannot insert VI in subpanel because VI is already open.

Shaun,Could you tell me how to connect the Sinking Digital module with mycontroller? I have no idea how to use it in my case without using therelay. I add here my real system diagram.

Best regards,

Thang Nguyen

OK. So your convinced you need a digital OP. (If you are insistent on NI products compatible with your chassis, I would have chosen the NI 9485 purely because it is 1/2 the price of a digital card but still 4x the price of other alternatives).

From your image I can guess that your sensor port is in fact a constantcurrent source. This makes sense to me as changes in resistance willyield a change in voltage as the load increases/decreases. (This is whyyour analogue output idea won't work).

If you think of a current sinking digital output as a transistor switchto ground. Then (relating that to your diagram) each Digitaloutput would be connected to the other side of the resistor. i.e between the resistor and common. If you are using it in this manner, it is important that you DO NOT connect the External supply to the Digital modules External Power Supply Terminal. This is because internally, each "transistor" is connected to the External supply pin via a resistor. You would in effect be putting this in parallel with all of your other resistors you are using. You also have to remember that it is "inverted logic". i.e setting the output to "1" grounds the device, but this can be changed in the NI configuration if it hurts your head.

Get the NI 9485 unless you are looking for fast IO and it will directly replace your switches and half the price...No brainer!

Thanks, ShaunR, it is a good idea. It would be a good inspiration in the other parts of my projects. But it is not so easy. I need to control the loop, because I have got more conponents inside that are dependent on "i" of the loop. So I need several buttons for start, pause, pause and..., stop connected with the loop directly. I think it can be solved with Event Structure inside the loop, but I can not use it properly. Thanks

To Neville D: No...

I think you are missing the point.

The image is an "example" of a counter. Not a solution to your project (that would be too easy ).

Look at what it does and how it works and apply it to your current "real" example.

Your dependency on the "i" iterator will cause you problems since it increments every loop execution. Your dependents need to use a counter (oooh...like the example ) that can be started and stopped regardless of how many times the loop executes.

How long is a piece of string?

Like I said. Twice as long (as 1/2 its length).

I am using NI 9263 Analog Output Module.

I found the module you told me, it's NI 9478. It's a $600 one

Not surprised.

Or ya could use one of these or something similar. Google for em.

USB Relay Board

You need "current sinking" digital outputs, then you can switch the resistors in direct without relays. The 9172is a chassis. what modules do you have currently?

You could also use the parallel port to switch some relays (be carefull about current though).

Or a non NI rs232 digital board (about $90).

Yet it takes practically no time at all to make p00p! (bad LabVIEW code, that is)

Amen...lol.

Just look at the internet toolkit and the Vision stuff

How long does it take to make GOOP?

Twice as long

Hi, I want to create an loop that can be controlled by buttons - it can be started, paused and stopped. I have found that this could be done with a help of Event Structure. The example (a counter) is below. Can you help me to run counting when it is started? Thanks

You can download it here: http://www.2shared.c...d2a/events.html (sorry, the file attachement failed)

First you will need to allow the time-out case to execute by wiring a value (say 100ms) to the blue icon in the top left hand corner. You will then have to use the state of the "Running" boolean to decide whether to increment the counter or not. You can use 2 shift rgisters (one for the state and once for the count).

This is thesort of thing you will want to use for the counter.

Hi Friends,

Recently i bought a PC which is having only one PCI slot. Others are PCExpress slots.

But i want to use few PCI compatible NI hardware same time.

Is there any hardware available in tha market like a adopter which can give more PCI Slots for my computer?

otherwise any idea how to convert PCExpress slot to PCI slot?

Thanks.

Regards,

Jai

NI also do PCIe cards.

Hi yall... So I may have to do this in order to get a 0-5V analog out signal up to the 0-10 V input signal required by a variable frequency drive. I was thinking of doing so by means of an op-amp configured to work as a non-inverting amplifier to increase voltage 2X, then put this through a unity-gain "power buffer" just to make sure the signal gets to were it needs to go (over long wires) without a whole lot of noise and without potentially messing up the op-amp. Should /shouldn't I do this? Any advice? (No, I can't just buy a daq card with 0-10 V output. Cmon, that would be too easy...)

Regards,

Mark Garnett

Sounds good to me. I would suggest darlingtons on the output if current is required.