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Programming the Status System 19Chapter 2
Example Program
/* status2.c *
* The following program provides an interactive command line interface
* to send SCPI commands to SCPI compatible instruments.
* This utilizes the MAV bit of the Status Byte in order to determine if
* the instrument is returning any output. It also automatically
* displays any error conditions that may result by querying the Standard
* event status register. */
#include <sicl.h>
#include <stdio.h>
/* Theses are Masks for the Status Byte */
/* all bits start at bit 0 */
#define MAV_MASK 0x10 /* MAV - bit 4 */
#define ESR_MASK 0x20 /* ESR summary - bit 5 */
/* These are Masks for the Standard Event Status Register */
/* all bits start at bit 0 */
#define QRY_ERR_MASK 0x04 /* query error - bit 2 */
#define DEV_ERR_MASK 0x08 /* device dependent error - bit 3 */
#define EXE_ERR_MASK 0x10 /* execution error - bit 4 */
#define CMD_ERR_MASK 0x20 /* command error - bit 5 */
/* This is the SRQ handler to check for Message Available (MAV)
* or any error conditions */
void srq_hdlr( INST id)
{
unsigned char stb;
char buf[255];
int esr;
int errnum;
char errmsg[100];
/* read the status byte to determine what caused the SRQ.
* Note: use ireadstb instead of *STB? because we want to
* clear RQS instead of reading the MSS bit in the status byte. */
ireadstb(id, &stb);
/* check if MAV caused the SRQ */
if( MAV_MASK == (stb & MAV_MASK))
{
/* message is available so read in the result */
iscanf( id, "%t", buf);
printf("%s", buf);
}
else /* check if Standard Event Status */
if( ESR_MASK == (stb & ESR_MASK))
{
/* read the standard event register to determine
* what caused the ESR summary bit to be set. This
* is necessary in order to get future SRQ’s from
* the Standard Event status group. */
ipromptf(id, "*ESR?\n", "%d\n", &esr);
/* check if an error caused the summary bit to get set */
if( (CMD_ERR_MASK == (esr & CMD_ERR_MASK )) ||
(EXE_ERR_MASK == (esr & EXE_ERR_MASK )) ||
(DEV_ERR_MASK == (esr & DEV_ERR_MASK )) ||