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TINA/Spice/OPA743: APA743

Part Number: OPA743
Other Parts Discussed in Thread: TINA-TI

Tool/software: TINA-TI or Spice Models

I am an experienced Pspice user but just trying to learn Tina TI. I have entered the Wein Bridge example circuit. I got the transient analysis to work and have added open circuit (VM 1,2..) connection to key circuit nodes. However I can't get the oscilloscope to work. I have adjusted the controls and can select the VM1, VM2 etc. test points but there is no signal present. Is there a mode to place the circuit in operation? DC values seem to be present. On page 9 of the Getting Started PDF, it says to place the cursor at the output of the simulated circuit. This does not seem to work. I can however select input "Channels" VM1, VM2 etc.

It's as if the circuit is not operating. What am I doing wrong?

  • Aubrey,

    Can you attach the TI-Tina file, so I can take a look at it.
    I don't use the oscilloscope tool often, so I will need to try it out myself.
  • While I would like to attach Example file, I see no way to do this. This form offers "Select Tags" as a button but no apparent way to attach files. This is the example from the Getting Started TI document. I am using Version 9.3.150.328 SF-TI which I downloaded yesterday from the TI site.

    On page 9 of Getting Started, it says to place the cursor at the output of the simulated circuit and adjust the controls in the virtual oscilloscope dialog box as needed. I cannot get the cursor to select any signals for viewing. It also says (top of page 9) that the software can be placed in a pseudo real-time simulation mode where virtual instruments can be used to observe the outputs while the circuit is operating. But there is no information on how to enable this mode.

    Apparently in order to view signals in analysis mode, a “VMx” “Open Circuit” meter must be placed in the schematic at desired test points. This is not explained but is as shown in the figures (Figure 8 for example). When I do that, these VM’s appear as “Channels” in the oscilloscope but selecting them still does not allow viewing of signals.

    Thanks,

    Aubrey Page

  • Hi Aubrey,

    Sorry you're having difficulties attaching files. Here is a good link on how to do so in E2E: https://e2e.ti.com/group/helpcentral/w/e2e/148.4-5-attaching-a-file 

    The only thing that has changed is "rich formatting" is now "Insert Code, Attach Files, etc...." You can click on the paperclip icon to attach files as well. If uploading the file doesn't work, try putting in a zip folder.

    I was able to play with the oscilloscope a bit and was able to get it working. When you are using it, are you clicking the “run” button? If you have the voltage meters set up in the circuit, that will start displaying the results. Under the “Channel” drop-down, you’ll be able to select which signals you’d like to see.

    Does that help?

    Paul

  • I did what you suggest. When I select "Run", it says collecting data forever. When I select a point where an AC signal should be present, I do get a DC signal. It's like only the DC startup values are present. You sent a link about attaching files but all is not clear. Where I am typing now (on the forum, immediately below your response) , there is no provision to attach files. Below where I am typing now there is blue text suggesting that to insert code, Attach files and more, that I should click there and follow thaExample 1.TSCt link. When I follow that link, a Word document of sorts appears allowing me to continue typing but there is NO paperclip. If I drag and drop, a giant figure appears in the text. I have left it there. There is no indication whatsoever that my file was attached. Are you familiar with the user interface that we see? 

  • Hi Aubrey,

    Your file did successfully attach, thank you. I am familiar with the interface you see - it can be hard to describe so maybe I'll write up a little document for the future.

    Anyhow, we've got your circuit now, I'd like a little time to see if I can better understand the TINA functionality. In the meantime, can you try running a transient simulation and see if the results make sense to you in that mode? You can access transient simulations by going to "Analysis" --> Transient..." If the results there don't make sense, I would check your circuit again to see if there are any potential issues.

    Thanks,

    Paul

  • Hi Aubrey,

    I see the same thing that you're seeing, the DC values when I first open the oscilloscope. Using your same circuit, I was able to get the oscilloscope working simply by changing the Time/Div from the default 10m to 5m. For some reason, when I do that the desired output sine wave shows up and everything works as expected. Can you try playing the with the time scale and see if you get the same behavior?

    If you were having trouble with the transient simulation, change the radio button selection from "calculate operating point" to "use initial conditions." It should work as desired then.

    -Paul
  • My previous post has disappeared?? Transient analysis works fine. In my previous post that has disappeared, I told how if I select Analysis, Options and check the box "Save all analysis results", then do a transient analysis, minimize it (maybe not necessary?), the oscilloscope works. I can see the AC signals. So after you post, above, I opened the file, opened the oscilloscope and it now works. Changing the time/div does what is expected but does not stop or start the oscilloscope. The probe function does not work for me. I can only view nodes that have a Open Circuit "Meter" attached to. So I then closed the file, re-opened it, in-checked the save all analysis button, closed the file and Tina, re-opened it and the oscilloscope still works. I can close Tina, re-open it, re-open the file, open the oscilloscope and it works. There's a bug/undocumented "feature" in there somewhere.
  • Hi Aubrey,

    We typically use transient analysis which is a little more straightforward; we don't have much experience with the oscilloscope function. I think you are right that there are some undocumented "features." For further assistance on using TINA, I would recommend posting in the simulation models forum: e2e.ti.com/.../234

    If you have any questions regarding op amps, please post. We'd be happy to help.

    -Paul