I'm using the "Open Datasocket Connection" to connect to a shared variable hosted on the remote computer. By the way, this has worked in the past but I had to re-install Windows OS and LabVIEW on the "remote" computer. So it it is probably due to something related to firewall, but like I said I think I have disabled everything...
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Re: Open datasocket connection error 42
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Re: get date time string in RT
I also recommended SNTP, and not doing it yourself.
The nice thing about SNTP is that it's handling the time syncronisation problem at the core. It adjusts CPU speed, and you'll never come close to the results if you do the corrections from LabVIEW. I'm not sure if NI-Timesync does that, I've not used it.
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Re: Get VI ref for LV executable set to allow multiple instances
Well, I'm nearly there. WIth further research I've found an example project that demonstrates one executable attaining an application reference to another executable. Now to see if I can use that reference to control the second executable.
One downside: it requires a VI Property being set, the TCP.Active property. Once set to True it accepts incoming VI Server requests. Thing is, I don't want to change the inherited executable. However, this tiny addition might be acceptable.
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Re: Create VI that multiplexes four inputs to a single output in a time division multiplexing format.
I guess my only real question is, how do I get two or more inputs to one output?
The two ways I know:
Merge - But for some reason, it only takes the top connection. The bottum signal never gets passed through to the output.
Case Structures - This is how I made it at first, I had 4 cases, and use a time elapsed box to switch cases. The only problem is, you cannot set the time for each case individually.
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Re: Relay and DAQ for switching a DC Motor
Sorry Raven. I mean no disrespect. But there has to be something supplying power to the motor. If it is a power supply, my suggestion might work. If not, so be it. I don't know the whole situation so i can only offer suggestions and let the OP decide.
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Re: Get VI ref for LV executable set to allow multiple instances
Can you post the example or its location if the Example Finder would locate it? and, do you mean "Short Name: Srvr.TCPActive"? That's one I've never played with before.
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Re: Relay and DAQ for switching a DC Motor
The motor is being powered by rectified power supply of 100V.
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Re: Relay and DAQ for switching a DC Motor
True. Usually when I hear of 120V, I'm thinking of AC power that is just directly powered from the lines and you need a basic contactor to connect and disconnect the motor. For DC motors, there has to be some source of DC power, and whether that is some source of power such as a DC voltage bus within a plant, or a dedicated power supply converting 120 VAC to 120 VDC specifically for that motor, we just don't know.
Either way, we need more details from the original poster, and can agree that a 12V 6A relay is not going to be usable as is.
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Re: Relay and DAQ for switching a DC Motor
If we're to use a contactor with relay, what should be its rating and specifications?
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Re: averaging images
thank you very much, dont know how i didnt think about that
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Re: Get VI ref for LV executable set to allow multiple instances
Thoric wrote:
I've read in another thread that you point to the exe in the machine name input.
Incorrect, as you've seen. The machine name input is just that. Since it's the same machine, you can use localhost (or I think an empty string also works). The key is the port number - each instance of VI Server listens on a different port, so that's what you have to configure. That's why the important property for what you want is not the Active property (that can probably be configured statically in the INI file), but the port property, which you need to somehow set dynamically to a different value for each separate instance (i.e one listens on port 4001, the next on 4002 and so on).
The service name is simply something that NI uses to abstract this a bit - there's an NI service which knows how to map these names to ports, but I have no idea exactly how this is configured. Presumably it's also done from the VI Server page/INI file. You don't actually need to use it.
I would suggest you also look at Norm's LVx examples, as I believe he does go into VI server connections between EXEs.
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Re: Relay and DAQ for switching a DC Motor
Does it mean we cannot use contactors for switching a dc motor? Also this is an institutional level project for building a water pumping system.
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Re: get date time string in RT
Hi jatinpatel. Have you accounted for timezones? RT usually uses UTC, the PC is usually local time.
Matt
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Re: Relay and DAQ for switching a DC Motor
You can use a contactor for a DC motor.
Look at something like this. SC-E04G-24VDC
But I still recommend talking to an electrical engineer familar with this stuff.
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Why does write datalog sometimes take up to 20 seconds to complete?
I have been using this vi for a number of years with no problem. I recently upgraded to LV 2013 and added some functions to the code but haven't changed the write datalog function.
Basically when I make a change to a front panel object I want to save the settings so I write it to a datalog file as in the ChangeCrop.png file. I have been doing this since LV 2010 with no issues. After upgrading to LV 2013 and adding some functions unrelated to the write datalog, occasionally now during the write process things come to a grinding halt for up to 20 seconds.
Using probes I narrowed it down to the Open/Create/Replace Datalog.vi in the datalogDiagram.png file. Watching the time stamp on the probes I found the 20 seconds between the path creation and the completion of the Open....Datalog.vi
Any ideas?
Alan
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Re: CIN and address
Should be the same when config the dll.
Both want a int pointer for input.
Don't know if LabVIEW like the second one or not.
Different when use the input:
in the first case, b is a pointer; *b is the integer.
in the second case, b in the integer, &b is address of b, ie. a pointer.
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Re: control 8 channels, with microsecond precision, outputs only
Hey,
If each row of data we're sending is 8 samples, and we can hold 2047 samples, then we can probably send about 255 rows before we run out of buffer space. One way we can get around this limit would be to write some of our samples, then start the task so that the device begins emptying, and then write more to the buffer after the task has been running for a little bit, but before the buffer is empty.
An easy way to do this would be to go through a time delay after the task starts, and then write again.
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Re: Relay and DAQ for switching a DC Motor
Most DAQ cards are only capable of supplying a few mA of current. in your case, the USB-6008 can supply 5mA. This is not enough current on it's own to power a coil on a relay of the size you need. There are some exceptions but you will pay good money for them. There are relay driver circuits that you can buy online that run off of TTL logic but they have to be plugged into another power source (wall plug, etc) in order to have enough power to flip the relays.
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Re: Create VI that multiplexes four inputs to a single output in a time division multiplexing format.
The case structure is the way you want to go. Instead of going by time, your subVI should just keep track of which one it sent out first. Use an Uninitialized Shift Register to keep track of which input to put out and then case them out. Let your top level VI worry about your timing.
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Re: get date time string in RT
Good point Matt. Both issues have to be addressed, though.
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