Agilent Technologies VXI E1439 - Manual (Page 169)

159
Agilent E1439 Programmer's Reference
Functions listed alphabetically
age1439_read
Reads scaled 32-bit floating-point data from the VME backplane register. This description also
includes the following function:
age1439_read64 reads scaled 64-bit floating-point data, implemented specifically for
VEE applications.
VXIplug&play Syntax
#include "age1439".h
ViStatus age1439_read(ViSession id, ViReal32 data[], ViInt32 sampleCount, ViPInt16
overloadPtr);
ViStatus age1439_read64(ViSession id, ViReal64 data[], ViInt32 sampleCount, ViPInt16
overloadPtr);
Description
age1439_read returns a block of floating-point data from the Agilent E1439 that has been scaled
to be in volts. The function waits for a block of data to be ready before attempting to read the
block.
These functions can only read data from the VME backplane register. The data port of the
Agilent E1439 must be set to AGE1439_VME by the age1439_data_port function for these
functions to be effective.
Note
When using this function, INSTR_REAL32 should be defined when compiling C/C++ programs.
To do this, in the Microsoft Visual Development environment, go to Project Settings, select the
C/C++ tab, and add INSTR_REAL32 to the preprocessor definitions. In a makefile or on a
command line, supply the option "/D INSTR_REAL32" to cl.exe. See the acvolts.exe example
programs.
This function performs the following sequence:
1. Checks for AGE1439_STATUS_READ_BLOCK and AGE1439_STATUS_
OVERLOAD.
2. If a block of data is NOT ready:
A. The function immediately returns the current measurement state.
3. If a block of data IS ready:
A. Data is read from the module.
B. It is converted to a floating point number and scaled.
C. The function returns any errors that were encountered when reading the data.
D. The value of the overload argument is set to indicate whether any overloads have
occurred since the last successful read.