Running PSpice 16 and Capture

PSpice 16 from Cadence/OrCAD is installed on all the workstations in the CSEE windows lab (Central 102). It uses the OrCAD schematic editor "Capture".

How to get started with Capture and PSpice 16

Before you use Capture or PSpice for the first time in the lab at OGI, you will need an OrCAD directory and a pspice.ini file. We have provided a script that will create the directory and file for you.

Click on Start
Click Run
Type \\emcee\projects\class\
Open the EE560 folder
Open the OGI-OrCAD_16 folder
Note: the full path is: \\emcee\projects\class\EE560\OGI-OrCAD_16
Double-click on Install_Pspice.bat to run the installation script.

This creates a directory for your Capture and PSpice files in your home directory: H:\OrCAD and copies the default pspice.ini configuration file to that directory.

PSpice simulations will fail ("model undefined" errors) unless you have a correct pspice.ini file.

The pspice.ini file is updated with your settings (library and part choices, for example) when you run PSpice. Another initialization file, capture.ini will be created and updated by Capture in H:\OrCAD for your Capture settings.

Now you are ready to run Capture and PSpice. You won't need to use the installation script again unless your pspice.ini file becomes corrupted.

The installation script also copies PSpice demo files for your use into: H:\OrCAD\Pspice_demos.

Starting Capture and PSpice 16

Starting Capture (mouse click sequence): Start, Programs, OrCAD 16, OrCAD Capture

Capture can take from 5 seconds to 3 minutes (!) to load. It is ready to use when the hourglass and brown OrCAD Capture splash screen go away.

You can create a new project or open an existing project. After you have entered your circuit you can start PSpice from within Capture.

Click on the blue arrow icon to start the PSpice simulation.

Creating a new project and schematic for simulating with PSpice

From within Capture:

File, New, Project

From New Project Window:

Type in desired name
Select "Analog or Mixed A/D
Select the directory location for your project
Click OK

Now from within "Create PSpice Project" window:

Select "simple.opj" or browse for another .opj file. For example, one of your existing project files or you can browse to H:\OrCAD\Pspice_demos and try one of the demo designs.

It is also OK to click on "Create a blank project" though it is usually easier to start from an existing project or start from "simple.opj".

Note: avoid the mistake of selecting File, New, Design. A "Design" is meant just for using Capture to draw a schematic. It allows you to draw a fine schematic, but you won't be able to simulate it with PSpice! You need a "Project" in order to enter a schematic that you can later simulate with PSpice.

Running the OrCAD supplied PSpice differential pair demo

At OGI:

First, copy the example files from C: to your home directory. With My Computer, find the folder:
C:\Orcad\OrCAD_16.0\tools\PSpice\Capture_Samples\anasim
Copy that folder (including all subfolders) to your H:\OrCAD folder (or any other convenient location).
Then from within Capture:
File, Open, Project
From the Open Project Window: specify the folder where you placed the example.opj file and click on Open.

Libraries of interest for EE550/EE560

Capture\library\pspice\source.olb vac, vdc, vsin,
0 (for ground) also hides here
Capture\library\pspice\analog.olb R,C,L
Capture\library\pspice\nom.lib
Use this in your PSpice library list (in simulation manager, libraries). It is a list of all the parts supplied with PSpice.

Libraries NOT OF INTEREST:

Capture\library\discrete.olb
won't work for PSpice simulation, they are only useful for drafting purposes (for using Capture to draw a schematic).

Libraries of interest for EE561/661

\\emcee\projects\class\EE560\OGI-OrCAD_16\PSpice_Demos\GM4_mos.olb

3uNMOS, 3uPMOS parts for analog CMOS IC design

This library and demo schematics for the GM4 parts will be downloaded to your home directory when you run the Install_PSpice.bat script (see above section "How to get started with Capture and PSpice 16").

Placing ground symbols

You can use any of the Capture library grounds as PSpice grounds as long as they are named "0". There is only one predefined part in Capture that is named "0"

Click on: Place, Ground, then select the library "source.olb" to find the only predefined "0" part. You can use any of the other Capture ground parts, but you will need to change the part name to "0" (zero).

For example, the conventional analog "arrow" ground can be found in the library "CAPSYM" named "GND_SIGNAL". To use it in a schematic as a PSpice ground, place the part and double click on it to change its name to "0" (zero).

Can't find the "0" ground symbol? You probably don't have "source.olb" included as one of your part libraries. Click on: Place, Ground, Add Library, then use the Look in: box to browse for the library or use the the file name box and type in:

C:\Orcad\OrCAD_16.0\tools\capture\library\pspice\source

then click on Open.

Installation note

We modified the startup properties for Capture so it starts in the Orcad directory within the user's home directory and maintains its initialization files there.

Target: "C:\OrCAD\OrCAD_16\tools\capture\capture.exe" -i "H:\Orcad"
Startin: "H:\Orcad"

By default PSpice uses the central pspice.ini file:

C:\OrCAD\OrCAD_16\tools\pspice.ini

which causes all users on that PC to share the same pspice.ini initialization file. We edited the registry to force PSpice to use H:\OrCAD\pspice.ini instead of sharing the central pspice.ini file. Each user has their own private capture.ini and spice.ini files for initialization and for storing preferences.

Problems and Solutions

Problem 1: PSpice runs, but I get error messages like:

"Model Q2n2222 used by Q2 is undefined"

Solution: you need to have a valid pspice.ini file in your H:\Orcad directory. See: How to get started with PSpice 16 and Capture at the top of this help page for installing a pspice.ini file.

You can also get this error if the PSpice library for the part is missing from your simulation profile. Add the library by clicking on PSpice, Edit Simulation Profile, Configuration files (tab), Category: library (pull-down list) . Then type in the path to the library or browse for it. Then click on "Add to Design" and OK.

Capture\library\pspice\nom.lib should be all you need listed for PSpice libraries in your simulation profile. It includes all the parts supplied with PSpice. If you are using a custom library or special libraries for an OGI class, you need to list them as well as nom.lib.

Note that the path to the library also has to be specified and be correct.

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This page was most recently revised on November 17, 2008.
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