National Instruments NI-488.2 NI-488.2 User Manual

Chapter 8 NI-488.2 Programming Techniques
© National Instruments Corporation 8-15 NI-488.2 User Manual
SRQ and Serial Polling with Device-Level Traditional NI-488.2 Calls
You can use the device-level traditional NI-488.2 call ibrsp to conduct
a serial poll.
ibrsp conducts a single serial poll and returns the serial poll
response byte to the application. If automatic serial polling is enabled, the
application can use
ibwait to suspend program execution until RQS
appears in the status word,
ibsta. The program can then call ibrsp to
obtain the serial poll response byte.
The following example shows you how to use the
ibwait and ibrsp
functions in a typical SRQ servicing situation when automatic serial polling
is enabled:
#include "ni488.h"
char GetSerialPollResponse ( int DeviceHandle )
{
char SerialPollResponse = 0;
ibwait ( DeviceHandle, TIMO | RQS );
if ( ibsta & RQS ) {
printf ( "Device asserted SRQ.\n" );
/* Use ibrsp to retrieve the serial poll response. */
ibrsp ( DeviceHandle, &SerialPollResponse );
}
return SerialPollResponse;
}
SRQ and Serial Polling with Multi-Device NI-488.2 Calls
The NI-488.2 software includes a set of multi-device NI-488.2 calls that
you can use to conduct SRQ servicing and serial polling. Calls pertinent
to SRQ servicing and serial polling are
AllSpoll, ReadStatusByte,
FindRQS, TestSRQ, and WaitSRQ. Following are descriptions of each of
the calls:
•
AllSpoll can serial poll multiple devices with a single call. It places
the status bytes from each polled instrument into a predefined array.
Then, you must check the RQS bit (bit 6 or hex 40) of each status byte
to determine whether that device requested service.
•
ReadStatusByte is similar to AllSpoll, except that it only serial
polls a single device. It is similar to the device-level NI-488.2
ibrsp
function.

National Instruments NI-488.2 NI-488.2 Specifications

General

Operating Systems	Windows, Linux, macOS
Programming Languages	C, C++, Python, LabVIEW
Interface	GPIB
Supported Standards	IEEE 488.2
Functionality	GPIB instrument control, data acquisition, and analysis

Summary

Chapter 1 Introduction

Setting Up and Configuring Your System

Describes how to set up and configure your GPIB system.

Chapter 2 Measurement & Automation Explorer (Windows)

Troubleshoot NI-488.2 Problems

Instructions for using the NI-488.2 Troubleshooting Utility.

Communicate with Your Instrument

Chapter 3 GPIB Explorer (Mac OS X and Linux)

Add a New GPIB Interface

View or Change GPIB Interface Settings

Chapter 4 Developing Your NI-488.2 Application

Interactive Instrument Control

Using the Interactive Control utility for instrument communication.

Choosing How to Use the NI-488.2 API

Guidance on selecting between traditional and multi-device NI-488.2 API calls.

Communicating with a Single GPIB Device

Checking Status with Global Variables

Explains how to use global status variables (ibsta, iberr, etc.).

Chapter 5 Debugging Your Application

NI Spy

Introduction to NI Spy utility for monitoring NI-488.2 calls.

Global Status Variables

Details on global status variables (ibsta, iberr, ibcnt, ibcntl).

NI-488.2 Error Codes

Explanation of error variable (iberr) and error codes.

Configuration Errors

Chapter 6 NI Spy Utility

Monitoring API Calls with NI Spy

Chapter 7 Interactive Control Utility

Chapter 8 NI-488.2 Programming Techniques

Termination of Data Transfers

High-Speed Data Transfers (HS488)

Describes the HS488 protocol for high-speed GPIB data transfer.

Enabling HS488

Instructions on how to enable the HS488 feature for GPIB interfaces.

Asynchronous Event Notification in NI-488.2 Applications

Using ibnotify for asynchronous notification of GPIB events.

Appendix C Error Codes and Solutions

GPIB Error Codes

Lists and describes GPIB error codes and their meanings.

EDVR (0)

Explains the EDVR error and provides solutions for accessing issues.

ECIC (1)

ENOL (2)