Thread Subject: Serial Communication

I am attempting to communicate with a device via a 9pin through serial connection. The device is a syringe pumping apparatus. When configured according to the manufacturer's instructions through hyperterminal, the apparatus can understand ASCI string data such as 'RUN', 'REV', and 'STP'as well as general config data like inputting syringe diameter size and discharge rate.

When I try to operate the apparatus through MatLab, however, it fails to respond. I create a serial port using the s=serial('COM1') command and open the port in MAtLab. I configure the baudrate, # of stop bits, etc using MatLab. I then use the fwrite() command. I attempt to write the string fwrite(s,'RUN'); or fwrite(s,'REV') to the device with nothing occurring. (i.e., I am attempting to send the string 'RUN' or 'REV' to the device).

The device is also capable of transmitting its current status, i.e., if it is stopped or running. How do I accomplish this? Do I create a for loop in order for MatLab to continuously read information from the device and report its status?

"steve smith" <stevesmith0518@comcast.net> wrote in message <gbthc9$8kj$1@fred.mathworks.com>...
> I am attempting to communicate with a device via a 9pin through serial connection. The device is a syringe pumping apparatus. When configured according to the manufacturer's instructions through hyperterminal, the apparatus can understand ASCI string data such as 'RUN', 'REV', and 'STP'as well as general config data like inputting syringe diameter size and discharge rate.
>
> When I try to operate the apparatus through MatLab, however, it fails to respond. I create a serial port using the s=serial('COM1') command and open the port in MAtLab. I configure the baudrate, # of stop bits, etc using MatLab. I then use the fwrite() command. I attempt to write the string fwrite(s,'RUN'); or fwrite(s,'REV') to the device with nothing occurring. (i.e., I am attempting to send the string 'RUN' or 'REV' to the device).
>
> The device is also capable of transmitting its current status, i.e., if it is stopped or running. How do I accomplish this? Do I create a for loop in order for MatLab to continuously read information from the device and report its status?
>

when you commanded the devide through hyperterminal did it reply before you hit enter? if not then you probably have to add \n or \r or some combination of those to the end of your fwrite string. also, what precision are you specifying for fwrite? to send characters you should specify 'uchar' as the precision, otherwise i don't know what it might default to.

Hi,

When I communicate with a microscope camera, I use this simple code to change status and get status reports:

s=serial('COM1');
set(s,'BaudRate',9600);
fopen(s);
fprintf(s, 'Illum 100'); %Illum 100 sets the Illumination to 100%

fscanf(s) %my camera answers with "Illum 100"

Hope this helps!

steve smith wrote:

> When I try to operate the apparatus through MatLab, however, it fails to respond.
> I create a serial port using the s=serial('COM1') command and open the port in MAtLab.
> I configure the baudrate, # of stop bits, etc using MatLab.

What do you configure the flow control as? It might require that flow control
be set to hardware. And I'd want to double-check exactly which line terminator
character it uses -- CR only, CR LF, LF only ?

Are you able to monitor the apparatus serial communications at all, even if just
via a blinking light, to see whether the data you are sending is getting out
the PC serial port?

Walter Roberson <roberson@hushmail.com> wrote in message <KWsEk.27$BT1.24@newsfe04.iad>...
> steve smith wrote:
>
> > When I try to operate the apparatus through MatLab, however, it fails to respond.
> > I create a serial port using the s=serial('COM1') command and open the port in MAtLab.
> > I configure the baudrate, # of stop bits, etc using MatLab.
>
> What do you configure the flow control as? It might require that flow control
> be set to hardware. And I'd want to double-check exactly which line terminator
> character it uses -- CR only, CR LF, LF only ?
>
> Are you able to monitor the apparatus serial communications at all, even if just
> via a blinking light, to see whether the data you are sending is getting out
> the PC serial port?

Hi Steve,

Try using fprintf instead of fwrite (after checking flowcontrol, parity and terminator settings on the device). fprintf sends the ASCI text followed by the terminator which the fwrite does not send by default.

Similarly for reading data back, if you expect ASCI/string response, fscanf is what you can use.

help fprintf
help fscanf

should give you more details.

However I agree with comments above that checking that settings on instrument/device matches that of the MATLAB object should be the first test.

Hope this helps

-Ankit