microcontroller interfacing with serial port using labview

[Hamidq]

Hi,

I was just reading this forum and wanted to ask a few questions since I’m doing something similar to this. My project involves using a communications method of sending data from a datalogger (model cr10x) to a remote location using Labview to view graphically. We plan to use a microcontroller to interface with the datalogger and send information via gsm through text to the remote location. Is it possible to adopt the same principles of using VISA for the driver even though you’re using the gsm to communicate data in text from the microcontroller to the remote PC with Labview. Also what controller do I need if I want to interface the microcontroller to the datalogger?

Regards,

Hamid.

[D_Biel]

Hi Hamid,

What interface does the data logger use? What sort of data are you receiving? How much data is it, and how fast is it coming?

Is there a reason you need to use gsm? What kind of transmitter and receiver are you using? There are easier methods to communicate if that is not a requirement of your project. I would recommed using labview on both ends, to read data, send it to a client over the internet (not GSM) then display it on the client.

[Hamidq]

Hi,

Sorry for the late response. The interface it uses is pc200w software which is used for beginners. The baudrate can vary up to 9600bps and there is no parity according to the manual i read up. The data we are recieving is based on temperature changes to the coolant of the diesel generator and its fuel level. It uses a 9-pin port output serial comms rs-232. It previously used a wavecom gsm device for communicating data to a laptop. I spoke to my supervsior and he said he would have to order a simcard which wont be available till after christmas. At the moment i'm trying to gather information about using a microcontroller and finding out how to connect that with the data logger. My aim is to search for a specific one and identify a way to connect the 9-pin port to the micro, if the micro has a 9-pin port. If not, is it possible to buy separate D-type connetors and manually attach each port using separate wires? 

Our objective in this project is to design a system that uses a microcontroller to enable connection to either gsm or tcp/Ip. The problem with the data logger is that it was never really meant for internet connection. Normally you have engineers that go out on site to connect a laptop to the serial to the data logger to check on the systems status. But with a micro you can enable the internet connection.

Regards,

Hamid

[wond3rboy]

Hi, there are a few glitches to your approach. Here are my questions/advice:

1. The datalogger uses a DB-9 connector right? Is the communication Synchronous or Asynchronous?. If its Asynchronous than you need only 3 pins from the connector, otherwise you will require more. Check the manual of the logger and determine which type of serial communication it utilizes.

2. For establishing serial communication with a microcontroller, you need that microcontroller to have a USART(Universal Synchronous/Asynchronous Receiver Transmitter) Module. Since you are just starting off with Microcontrollers, it would be a nice thing to tell us about your requirements, may be we could recommend one for you as well.

3. If you are using a micro to just send data to LabVIEW, you can skip the micro and use a USART IC in between to directly control the datalogger from LabVIEW and remove the hassle of learning to use a micro(you can keep that for another bright day).

4. For starting off with communicating serially with LabVIEW check out the examples that ship with it. Try what you can and we'll help you with carrying it forward. I'll end it now. Good Luck

[Hamidq]

Thna

[Hamidq]

Sorry about that last message, please ignore, it was by accident.

Anyway, thanks for the advice wond3rboy. Could you tell me a bit about the USART IC? I'm considering in using your last approach, by leaving out the micro and just use the USART IC. Our datalogger uses synchronous communication.

the last bit you mentioned with LabVIEW check out the examples that ship with it - Will NI have examples on this? Or does LabVIEW hold any demos/simulation examples?

Hamid.

[D_Biel]

Do you communicate with the microcrontroller using a serial interface? If so, then VISA will work and there are plenty of examples and community support for serial communication. For GSM communication, there is a little less information available and it requires a GSM toolkit.

[wond3rboy]

Hi, there are a lot companies that manufacture USART ICs, what are the operating voltages of your Datalogger? Does it use 5v or 3.3v for output. Try Octopart to search for a convenient IC. For the example part use NI Example finder from the the help drop down menu. Search for 'Serial'. If you dont find than i can upload them for you.

[Hamidq]

Hi, the operating voltages for the dataloggera is 5v output. What ports would i need to be able to connect it with the dataloggers 9 pin port serial. Also how would i connect the wi-fi port or ethernet to the chip?

[wond3rboy]

Hi, as you say that your datlogger sends data serially? Than you just use a MAX232 to convert the 5v logic to RS232 levels,  and connect the other end to the computer. Did you read from the manual whether it uses Synchronous or Asynchronous Transmission. You have already specified the baudrate as 9600, no parity right? Can you post the link to your data loggers users manual/data sheet? 

For the Ethernet part you would need a separate IC and most probably a micro in between(haven't seen an ethernet IC that accepts serial data). For the Ethernet part i believe LabVIEW would do if you are having a computer at the other side. Its childs play with it. WIFI is different though. Havent done WIFI with LabVIEW yet. There are micros for that as well but than you are talking about 16 bit and 32 bit cores.