User`s manual

Chapter 6 167

Advanced Operations

HP-IB Service Requests

The Test Set is capable of generating a “service request” when it

requires the Active Controller to take action. Service requests are

generally made after the Test Set has completed a task (such as making

a measurement) or when an error condition exists (such as an internal

self-calibration has failed).

The mechanism by which the Active Controller detects these requests is

the SRQ interrupt. Interrupts allow for efficient use of system

resources, because the Active Controller may be executing a program

until an SRQ interrupt occurs. If SRQ interrupts are enabled in the

Active Controller, the occurrence of an interrupt can initiate a program

branch to a routine which “services” the interrupt (executes some

remedial action). The operating and/or programming manuals for each

controller describe the controller’s capability to set up and respond to

SRQ interrupts.

This section describes the steps necessary to properly configure the Test

Set to request service using the Service Request (SRQ) function.