How to read data from TDS3012B oscilloscope?

[20041221]

Hi guys,

I try to read waveform data from the TDS3012B oscilloscope through the RS232 port, the scope is communicating with PC through COM port. I try to write some c program to send command to the scope, however it seems no response? Does anyone has experience about this kind of communications? Really appreciated any help from you.

Many thanks in advance,

Lidan

 

[analogkid2digitalman]

Lidan:

Some basic serial interface tips:

1. Verify proper cabling and that is scope set up for RS232 communications
2. Confirm port settings on both PC and scope- baud, stop&data bits, parity, etc
3. Test basic communications first in Windows Hyperterminal- issue commands and verify proper responses.
4. Then start writing C application, include proper port opening, conficuration, error handling, and close port prior to exiting application.

-Pete

Wheels within wheels / In a spiral array
A pattern so grand / And complex
Time after time / We lose sight of the way
Our causes can't see / Their effects.

 

[VEBill]

I highly agree with item 3 by ak2dm (above). Get the simplest possible communications established before you try to do anything else.

 

[20041221]

thanks for the tips.

Now I try to connect the scope with the Hyperterminal, but I can't enter command and there is nothing shows up. By the way, I use a DB9 Female/Female cable connect scope with my PC. When I connect a wireless modem with my PC, the hyperTerminal is fine and working well, I was thinking if there is any special setting for the scope. Any ideas?

Lidan

 

[analogkid2digitalman]

Have you tried swapping pins 2 and 3 at one end of the cable (null modem configuration)? I would refer to scope manual or tech assistance to determine cabling. Handshaking may or may not be required. Waveform data transfers can contain a lot of bytes, I would use handshaking if allowed.

Wheels within wheels / In a spiral array
A pattern so grand / And complex
Time after time / We lose sight of the way
Our causes can't see / Their effects.

 

[20041221]

Hi Pete,

I know I have to use a cable in null modem configuration, but I don't know how to swap pins? Could you tell me more detail about how to swap them?

Many thanks,

Lidan

 

[analogkid2digitalman]

I would first verify current cable wiring with an ohm-meter.
Pin 2 on one end should make continuity with pin 3 on the other end and visa-versa.

If that is not an option, then if the clamshells at each end of the cable can be opened (if it is a sealed, molded cable assembly then it can't be opened) then just open one end and swap pins 2 and 3 by unsoldering wires, swap, and resoldering.

All else failing, just go out and purchase a known 9-pin null modem cable.

Wheels within wheels / In a spiral array
A pattern so grand / And complex
Time after time / We lose sight of the way
Our causes can't see / Their effects.