Applications used:

TYX PAWS Studio 1.34.6

Agilent IO Libraries Suite 14.2.msi (IVI Shared Components v. 1.2.1)

Instrument driver 34401 IVI-COM 1.1.0.11

Microsoft Visual Studio C++ 6.0

Operating System Windows XP Pro SP2

Introduction:

This document will help to create a WCEM driver that will help interface the ATLAS code with an IVI-COM instrument driver using the TYX Paws Developer Studio.

As an example we use the IVI-COM driver for Agilent 34401A DMM.

The assumption will be made that the user is familiar with the Paws Developer Studio.

1 List of requirements

In the PAWS Project example presented in this document we set a goal to implement the following functionality related to the IVI-COM driver:

· During the initialization, set the following:

o Resource Name to GPIB address 23

o IDQuery to false

o Reset to true

o Simulate to true

· Configure the DCVoltage to a range of 1.5 with a resolution of 0.001.

· Set the Delay property to 0.01.

· Take a reading with a timeout of 1000.

· Close the driver session.

2 Creating the environment:

2.1 Creating PAWS Project

Open PAWS Studio application and navigate to File\New Project… You should see the following images:

Figure 1

Figure 2

You will need to enter the project name and the directory for your project. In this case, we can call the project IVI_COM_DMM. The directory can be anywhere that is convenient for you on your system.

Figure 3

At this point, you can click on OK.

Now you need to add and ATLAS file to your project and a device database description. The ATLAS file will be part of an ATLAS project module and the device database will be part of the device database project module. After creating a new PAWS project, you are given an ATLAS project module. You just need to add a new file to that module. You will then have to manually add a device database project module before adding a device database file to it.

2.2 Adding Paws Files to the project

Adding the ATLAS file to the ATLAS project module: We will chose to call this file atlas.atl. From the toolbar, you need to select File\New File…:

Figure 4

This will yield to the following window:

Figure 5

Check the option to add the file to the project
And enter the following File Name: atlas as shown below:

Figure 6

· Copy the following source code and paste it into the atlas.atl file:

001000 BEGIN, ATLAS PROGRAM 'IVI-COM DMM' $

001010 REQUIRE, 'DMM-DC-VOLTS', SENSOR(VOLTAGE), DC SIGNAL,

CONTROL, VOLTAGE RANGE -300 V TO 300 V,

MAX-TIME RANGE 1 SEC TO 5 SEC,

CNX HI LO $

001110 DECLARE, VARIABLE, 'MEASURED' IS DECIMAL $

E02000 OUTPUT, C'\LF\ATLAS PROGRAM STARTS HERE\LF\' $

002200 VERIFY, (VOLTAGE INTO 'MEASURED'),

DC SIGNAL USING 'DMM-DC-VOLTS',

NOM 0 V UL 0.5 V LL -0.5 V,

VOLTAGE RANGE -0.5 V TO 0.5 V,

MAX-TIME 5 SEC,

CNX HI X20-2 LO X20-3 $

002300 OUTPUT, C'DC VOLT MEASUREMENT 1 = ', 'MEASURED', C' VDC' $

999000 OUTPUT, C'\LF\ATLAS PROGRAM ENDS HERE\LF\' $

999999 TERMINATE, ATLAS PROGRAM 'IVI-COM DMM' $

· This is what it will look like in your Paws Studio:

Figure 7

· Now we are ready to add a device database module.

· Go to File\New Module… Click on DEVICEDB and accept the selection with OK.

Figure 8

· Then navigate to File\New File… and choose DEVICE file. Click OK.

· You will see the following window:

Figure 9

You can now add the file to the project by checking Add to project:.
You also need to add the file name dmm to File Name:.

Figure 10

· You can now click on OK.

· You project environment now should look like this:

Figure 11

· In the dmm device database file called dmm.ddb, copy the following source code and paste it into it:

begin dev DMM;

cnx hi DMM-Hi, lo DMM-Lo;

begin FNC = 101; ** DC Voltage Measurement

sensor(voltage)dc signal;

control

{

voltage range -300 v to 300 v continuous;

}

end; ** DC Voltage Measurement

end; *end dmm

Note: To understand the content of this file, please refer to the Paws Studio online help.

· The content of this file will look like this in the Paws Studio:

Figure 12

2.3 Adding the C++ WCEM interface and C++ files to the Paws project:

At this point you have the basic components for the project in place. You can now build the project by selecting Build\Rebuild All:

Figure 13

The next step would be to add the WCEM interface C++ functions invoked by the ATLAS code. Those C++ functions will include the IVI-COM calls to control the instrument. First we will need to add a WCEM project module. Then we will need to create a mapping between the ATLAS and the C++ functions. Finally, we will need to populate those C++ functions with the IVI-COM function calls.

In order to accomplish that we will take the following action:

Go to File\New Module… and click on CEM.
Then enter WCEM in Module Name:

Figure 14

· You can now click on OK.

· Now, in order to create the mapping between the ATLAS code and the C++ functions, go to View\CEM Wizard… You should see the following images:

Figure 15

In order to create the mapping between the ATLAS code and the C++ function calls, please follow the steps below:

This will lead to the following window:

Figure 16

o Click on the Advanced tab and you will see the following window:

Figure 17

o In order to deal with some of the environmental operations that are needed to connect to the IVI-COM driver, check Load, Unload and Disable CEM Logging check boxes.

Figure 18

You can now click on OK.

o Back to the previous widow, right click on DMM label and click on Add Interface Function:

Figure 19

This will lead to the following window.

Figure 20

For a series of ATLAS actions, you will need to enter the C++ function name that you wish to invoke. For the Setup Action, please enter DMM_Setup for the User Function Name(s).

Figure 21

Press OK.

Note: To obtain more details on how to use CEM Wizard you can refer to the PAWS Studio Help System.

For Fetch, Init, and Reset, you need to enter the following names: DMM_Fetch, DMM_Init and DMM_Reset.
Once you have added the four function names, you can click on OK.
This will add several files to your WCEM module:

Ctrl.cpp
DMM.cpp
Error.cpp
Wrapper.cpp
Key.h

Ctrl.cpp will include the doOpen and doUnload functions. DMM.cpp will include the four DMM_ functions.
The paws project environment should look like this:

Figure 22

You are also required to add a new *.h file to the project to include some necessary code that we will see later in this tutorial.

In this example we will call this file DMM.h.

In order to do this, you will need to right-click on the WCEM module and select Add New File to Module…
This will give you the following window:

Figure 23

o You need to check Add to project and, select CEM header file and enter DMM in File Name:

Figure 24

o You can now press OK.

3 Connecting to the IVI-COM instrument driver

3.1 Connecting to the IVI-COM environment:

You will need to add the following code in your DMM.h file:

#ifndef __DMM_h__

#define __DMM_h__

#include <atlbase.h>

#include "Visacom_i.c"

#import "IviDriverTypeLib.dll" named_guids, raw_interfaces_only, raw_native_types no_namespace

#import "IviDmmTypeLib.dll" named_guids, raw_interfaces_only, raw_native_types no_namespace

#import "Agilent34401.dll" named_guids, raw_interfaces_only, raw_native_types no_namespace

#endif

Your DMM.h file in your PAWS project will look as follows:

Figure 25

Note: This header file allows to access to the COM environment, the IVI specific environment and the environment specific to the device, which is in our case an HP34401A instrument.

· Summarizing the effort of adding the WCEM Interface functions you should have the following files generated in your WCEM module:

o Key.h

o DMM.h (manually added)

o Ctlr.cpp with the doUnload() and doOpen() functions

o DMM.cpp with the DMM_Setup(), DMM_Fetch(), DMM_Init() and DMM_Reset() functions

o Error.cpp

o Wrapper.cpp

· The Paws Studio should now look like this:

Figure 26

· Let us start with including all the declarations to the ctrl.cpp and DMM.cpp files.

· In ctrl.cpp we need to add the following code:

#include "DMM.h"

extern CComPtr<IAgilent34401> driver;

extern CComPtr<IAgilent34401DCVoltage> pDMMDCVolt;

extern CComPtr<IAgilent34401Trigger> pDMMTrig;

extern CComPtr<IAgilent34401Measurement> pDMMData;

extern HRESULT hr;

The code will appear as follows in your Paws project:

Figure 27