VXI VT1422A, Руководство пользователя

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Creating and Running Algorithms 183 Chapter 6
Arithmetic Operators:
add + , subtract - , multiply * , divide /
Note: See “Calling User Defined Functions” on page 193.
Assignment Operator:
=
Comparison Functions:
less than < , less than or equal <= , greater than
> , greater than or equal >= , equal to == , not equal to !=
Boolean Functions:
and && or || , not !
Variables:
scalars of type static float and single dimensioned arrays of
type static float limited to 1024 elements.
Constants:
32-bit decimal integer; Dddd ... where D and d are decimal digits but D is
not zero. No decimal point or exponent specified.
32-bit octal integer;
0oo ... where 0 is a leading zero and o is an octal digit.
No decimal point or exponent specified.
32-bit hexadecimal integer;
0Xhhh ... or 0xhhh ... where h is a hex digit.
32-bit floating point; ddd. , ddd.ddd , ddde
±
dd , dddE
±
dd , ddd.dddedd
or ddd.dddEdd where d is a decimal digit.
Flow Control:
conditional construct if(){ } else { }
Intrinsic Functions:
Return minimum; min(<expr1>,<expr2>)
Return maximum; max(<expr1>,<expr2>)
User defined function; <user_name>(<expr>)
Write value to CVT element; writecvt(<expr>,<expr>)
Write value to FIFO buffer; writefifo(<expr>)
Write value to both CVT and FIFO; writeboth(<expr>,<expr>)
Example Language
Usage
Here are examples of some Algorithm Language elements assembled to
show them used in context. Later sections will explain any unfamiliar
elements seen here:
Example 1;
/*** get input from channel 8, calculate output, check limits, output to ch 16 & 17 ***/
static float output_max = .020;
/* 20 mA max output */
static float output_min = .004; /* 4 mA min output */
static float input_val, output_val; /* intermediate I/O vars */
static float remote_input_val; /* I/O var for remote channel*/
input_ val = I108; /* get value from input buffer channel 8*/
remote_input_ val = I14001; /* get value from input buffer channel 4001*/
output_val = 12.5 * input_val; /* calculate desired output */
if ( output_val > output_max ) /* check output greater than limit */
output_val = output_max; /* if so, output max limit */
else if( output_val < output_min) /* check output less than limit */
output_val = output_min; /* if so, output min limit */
O116 = output_val / 2; /* split output_val between two SCP */
O117 = output_val / 2; /* channels to get up to 20 mA max */
writecvt(remote_input_val,501); /* remote chan val to CVT element 501 */