Programming the Status System

In This Subsection

General Status Register Model

This subsection discusses the structure of the status system used in SCPI instruments, and explains how to program status registers. An important feature of SCPI instruments is that they all implement status registers the same way. The status system is explained in the following paragraphs:

General Status These paragraphs explain the way that status Register Model registers are structured in SCPI instruments. It

also contains an example of how bits in the various registers change with different input conditions.

Required These paragraphs describe the minimum required Status Groups status registers present in SCPI instruments. These

startus registers cover the most frequently used functions.

The generalized status register model shown in Figure l-33 is the building block of the SCPI status system. This model consists of a

condition register, a transition filter, an event register and an enable ’ register. A set of these registers is called a status group.

 

Condition

Transition

Event

Enable

 

 

Register

filter

Register

Register

 

Bit

0

 

 

 

 

Bit

1

 

 

 

Summary

Bit

2

 

 

--)

Bit

 

 

 

 

Bit

3

 

 

 

 

Bit Name f

Bit Number

Figure l-33. Generalized Status Register Model

When a status group is implemented in an instrument, it always contains all of the component registers. However, there is not always a corresponding command to read or write to every register.

Condition Register

The condition register continuously monitors the hardware and firmware status of the instrument. There is no latching or buffering for this register, it is updated in real time. Condition registers are read-only.

Getting Started Programming l-101