VXi VT1529A/B 사용자 설명서
Creating and Running Algorithms 221
Overall Program
Structure
The preceding discussion showed the differences between individual
statements in BASIC and 'C'. Here it will be described how the VT1422A's
Algorithm Language elements are arranged into a program.
statements in BASIC and 'C'. Here it will be described how the VT1422A's
Algorithm Language elements are arranged into a program.
Here is a simple example algorithm that shows most of the elements
discussed so far.
discussed so far.
/*
Example Algorithm to show language elements in the context of a complete
custom algorithm.
custom algorithm.
Program variables:
user_flag
Set this value with the SCPI command ALG:SCALAR.
user_value
Set this value with the SCPI command ALG:SCALAR.
Program Function:
Algorithm returns user_flag in CVT element 330 and another value in CVT element 331
each time the algorithm is executed.
When user_flag = 0, returns zero in CVT 331.
When user_flag is positive, returns user_value * 2 in CVT 331
When user_flag is negative, returns user_value / 2 in CVT 331 and in FIFO
each time the algorithm is executed.
When user_flag = 0, returns zero in CVT 331.
When user_flag is positive, returns user_value * 2 in CVT 331
When user_flag is negative, returns user_value / 2 in CVT 331 and in FIFO
Use the SCPI command ALGorithm:SCALar followed by ALGorithm:UPDate to set
user_flag and user_value.
user_flag and user_value.
*/
static float user_flag;
static float user_flag;
/* Declaration statements (end with ; ) */
static float user_value;
writecvt (user_flag,330);
/* Always write user_flag in CVT (statement ends with ; ) */
if (user_flag )
/* if statement (note no ; ) */
{
/* brace opens compound statement */
if (user_flag > 0) writecvt (user_value * 2,331);
/* one-line if statement (writecvt ends with ; ) */
else
/* else immediately follows complete if-statement construct */
{
/* open compound statement for else clause */
writecvt (user_value / 2,331); /* each simple statement ends in ; (even within compound ) */
writefifo (user_value); /* these two statements could combine with writeboth () */
writefifo (user_value); /* these two statements could combine with writeboth () */
}
/* close compound statement for else clause */
}
/* close compound statement for first if */
else writecvt (0,331);/* else clause goes with first if statement. Note single line else */