HP Drive manual Set the Trigger and Trigger Delay, CheckErr hp34401aRead session, 1000, &reading

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•Simulate=1 in the Options parameter sets the driver to simulation mode

•&session assigns the Instrument Handle to the variable “session” defined above

Configure the Instrument

1To set the range to 1.5 volts and resolution to 0.001 millivolts, type:

checkErr( hp34401a_ConfigureMeasurement (session, HP34401A_VAL_DC_VOLTS, 1.5, 0.001));

Set the Trigger and Trigger Delay

1To set the trigger source to immediate and the trigger delay to 0.01 seconds, type:

checkErr( hp34401a_ConfigureTrigger (session, HP34401A_VAL_IMMEDIATE, 0.01));

Set the Reading Timeout/Display the Reading

1To take a reading from the instrument and to set the reading timeout to 1 second (1000 ms) type:

checkErr( hp34401a_Read (session, 1000, &reading);

Note: The Read function takes a reading from the instrument and assigns the result to the variable “reading” defined above.

2To display the reading, use a printf statement. Type printf (“Reading = %f”, reading);

Close the Session

To close out the instance of the driver and free resources, type

If (session)

hp34401a_Close(session);

The final code should contain the code below:

#include "stdafx.h" #include <hp34401a.h>

#ifndef checkErr

#define checkErr(fCall) \

if (error = (fCall), (error = (error < 0)? error : VI_SUCCESS)) \

{goto Error;} else error = error

Chapter 2