Problems with serial device

[rjh123]

Hey everyone,

I'm quite new at labview

I hooked up a rs 232 serial device to my computer and installed the drivers for it and all that good stuff. I opened hyperterminal and had no problems communicating with the module.

When I opened one of the serial example VIs in labview I tried sending commands and I kept getting an error message saying it had timed out.

BUT

When I sent the same command 5 or 6 times at once i.e

VM 1 0

VM 1 0

VM 1 0

VM 1 0

VM 1 0

my module recieves the command and functions fine.

What did I do wrong???

[Dennis_Knutson]

What is the exact string you entered into the 'string to write' control? Did you include the CR and LF (\r and \n)?

[rjh123]

I tried it like

VM 1 0

which worked in hyperterminal but labview timed out.

I just tried

VM 1 0\r\n

and it still timed out.

When I type

VM 1 0

VM 1 0

VM 1 0

VM 1 0

VM 1 0

my module clicks and valve #1 closes like the code told it to but the read string says "VM 1 0VM 1 0 ERROR: WRONG # OF ARGS".

[Dennis_Knutson]

Perhaps you need to add some inter-character delay like Hyperterminal. Try the options here.

[rjh123]

Thanks for the suggestion but I still couldnt get it to work.

Someone else suggested that the reason it times out when I send the command once is because the vi might be expecting a certain amount of bytes. The more I type in the string to write box the quicker it responds but I dont know how to change that.

Is that a possibility?

[Albert.Geven · Accepted solution]

Hi

Did you type the \r \n characters in "\' Codes Display" mode ?

right click on the string and select this mode before typing \r \n

[rjh123]

THANK YOU!

I switched to codes display and it works perfectly now!