Serial Communication

[xseadog]

Hi again
With reference to your serial ports
JoeLabView posted a very good thread that is very enlighting

http://forums.ni.com/ni/board/message?board.id=170&message.id=111793&query.id=0#M111793

xseadog

[JohnGalt]

So, I have tried testing the cables as Dennis suggested, and I don't think they are straight through.  To make sure, though, I will try to diagram it. They are labeled Male and female.

Male                                 Female
*1*2*3*4*5                         *5*4*3*2*1
 *6*7*8*9                             *9*8*7*6
Thus I shall try to find a straight through cable. I tried the hard reset, but it was through the old cable, so that same thing might be the problem. I will be SO annoyed if the cable is the issue, working this hard because someone bought the wrong cord...... I will look at the KC's Vi and the other posts when I have time later in the day, or week, orwhatever.

Thank you all, you may have saved me.

[tbob]

To determine if your cable is a straight or null modem cable, use an ohmeter.  A straight cable has pin 1 on one end connected to pin 1 on the other end.  Both pin 1s are on opposite sides as you show in your diagram because of the gender change, but they are still pin 1.  As the name implies, straight cables tie pin 1 to pin 1, pin 2 to pin 2, and so on.  A null modem cable has a different configuration:

Side 1   Side 2

1           4 (or sometimes not connected)

2           3

3           2

4           1 or 6 or both

5           5

6           4

7           8

8           7

9 is not used.

[JohnGalt]

Okay, so my cables are straight through. I am sad, I thought maybe that was the problem and that replacing that would fix this whole ordeal..... meh. Oh well, I will try other ideas. Keep them coming if you have any.

Thanks again

[xseadog]

Hi J

please advise your current status with your problem ?

If you still have problem -have you attempted to just communicate with one RS232 device? Also is that via installed serial card or

serial port pre installed on PC?

Have faith

xseadog

[JohnGalt]

Current status, still unfixed. But I am now going to have to add A/D communication for other devices and the Tektronix has changed so it is serial now as well, but that is beside the point. I have tried doing one at a time, and through the serial port that came with the computer even. Nothing. The pre-placed port doesn't appear to work in Labview.

Thanks anyway.

[xseadog]

Hi John
seems like you inthe doledrums
Have you tried to use  NI's MAX ?
At the same time NI spy?
MAX when initinalised will search for all connected insruments to serial ports and all other appropiate connections.
NI spy acts as a passive monitor but does reveal which commands have been sent and recieved plus the timing.

Don't hesitate to ask

Xseadog

[shoneill]

Do your instruments send data unsolicited, or do you need to send a query first?

If they require a query, can you give us an example for one instrument which isn't running at the moment?  An example as to what kind of answer should come back would be useful too.

I might whip up a program to test different serial port settings if I have time.

Shane

[JohnGalt]

xseadog: I have tried MAX, nothing happened. Still get the timeout error that always accompanies the Labview reading. No matter how high I set the timeout, I still get it. I have not tried NI Spy yet, though. It sounds useful. I shall look for it on my program list. I am sure I have it. Doldrums? Yeah, maybe a bit. Just bored trying to get this bloody program working. I actually get bored at work, something I have never done before. Thanks for the concern though.


Shoneill: My instruments do not send data unsolicited. I have to send a command. (There are instruments that do send data unsolicited?!?) I know I have the right command, at least for the Omega MDSi8 Temperature Controller. I have called Omega twice to confirm it. It is indeed X01. I have tried adjusting port settings, but the program would be really helpful. That way I can make sure I am doing it right. Thanks again.

[JohnGalt]

OK. I am sorry, I couldn't figure out how to use NI Spy. As far as I can tell, I need to make some kind of other program to run it, but I don't know how to do it. It won't let me start a capture because something is not set up for that> I don't know what that something is.