remote monitorng and control by using Labview 8.0

[Dennis_Knutson]

You are asking questions that are about impossible to answer because you haven't provided any details on the sensors. Does each sensor constant broadcast or do they require the receipt of some sort of command first in order to reply back with the data? If it's the first case, then you could apply the client model to your program. If it's the second, then you would have something like a a TCP Write followed by a TCP Read. Post the data sheet of the sensors or a link to the information.

When you say you are thinking of a structure, do you mean sequence structure? You will probably have a sequence of events but there is almost certainly no need to use a sequence structure. The functions you will use will have error in/error out connections and that is a better way to enforce execution order. Remember that LabVIEW is a dataflow language.

[mf_hussin]

Hi Dennis,

Firstly, I just want to say sorry about the huge mistake that I make. Actually, my project not recive the data directly from the tranducer but from the wireless device instead. I will explain briefly about this wireless data acqusition project. Our measument is taking from the transducer then it will be connectted to protection device. The signal that we try to get after the protection device is +/- 10V. Then this signal will convert to digital using ADC. After the coversion it will send the data to Pc's by using wifi. Labview is used to do the monitoring and data analysis. the problem is how I'm going to interface this device between the transmitter and reciver. At the transmitter it going to have 4 unit and 1 unit at the reciver. How I'm going to differentiate each data that I receive from ecah transmitter?

Here I attach the specification of the wifi and router.

Regards,

MF Hussin

[Dennis_Knutson]

You are going to have four different widgets connected to four differerent Airborne Direct Device Servers, correct? Each one of those servers will have a unique IP address, correct? This sort of setup would be similar to connecting your widgets directly to the computer with 4 separate com ports. If you were to use VISA to talk to 4 different instruments connected to 4 different com ports, then each instrument would be identified by a unique VISA Resource Name (i.e. com1, Com2, etc.). In your case, the unique VISA resource names would be the 4 different IP addresses (i.e. 192.168.101.1, 192,168.101.2, etc.). If you wanted, you could prbably debug the communication to the widget by directly connecting them to a com port on your pc. This would let you get an understanding of the commands and responses. Then, and this is the beauty of VISA, when you connected the widgets to the wireless servers, all you would have to do in your program is change the VISA resource name. The actual syntax in VISA for a TCP connection is 'TCPIP::host address::port::SERVER'. You could also try 'TCPIP::host address::INSTR' but I think this is reserved for a special class of TCP enabled instruments.

Using the bulti-in TCP functions is an option as well. There you would use TCP Open, TCP Write, TCP Read, etc. I think the VISA approach might be easier though, because of the ability to debug with a direct serial connection.

[mf_hussin]

Hi Dennis,

I has spoke to NI Application Engineer regarding this matter, he suggest me to used TCP instead of VISA. He mention usually VISA is suitable with serial and GPIB. By the way I will try both and see how it goes. Thank for your help and hope to keep in touch.

Take care.