Chapter 5 Remote Interface Reference

The SCPI Status System

The Status Byte Register

The Status Byte register group reports conditions from the other register groups. Data in the instrument’s output buffer is immediately reported on the “Message Available” bit (bit 4). Clearing an event register from one of the other register groups will clear the corresponding bits in the Status Byte condition register. Reading all messages from the output buffer, including any pending queries, will clear the “Message Available” bit. To set the enable register mask and generate an SRQ (service request), you must write a decimal value to the register using the *SRE command.

Bit Definitions – Status Byte Register

 

 

Decimal

 

 

 

 

Bit Number

Value

Definition

 

 

 

 

 

 

 

 

0

Not Used

1

Returns “0”.

 

 

1

Alarm Condition

2

One or more bits are set in the Alarm Register

 

 

2

 

4

(bits must be enabled).

 

 

 

 

 

Not Used

Returns “0”.

 

 

3

Questionable Data

8

One or more bits are set in the Questionable

 

 

4

Message Available

16

Data Register (bits must be enabled).

 

 

Data is available in the instrument’s output buffer.

 

5

5

Standard Event

32

One or more bits are set in the Standard Event

 

6

Master Summary

64

Register (bits must be enabled).

 

One or more bits are set in the Status Byte

 

 

7

Standard Operation

128

Register (bits must be enabled).

 

 

One or more bits are set in the Standard

 

 

 

 

 

Operation Register (bits must be enabled).

 

 

 

 

 

 

 

 

The Status Byte condition register is cleared when:

∙You execute the *CLS (clear status) command.

∙You read the event register from one of the other register groups (only the corresponding bits are cleared in the Status Byte condition register).

The Status Byte enable register is cleared when:

∙You execute the *SRE 0 command.

∙You turn the power on and have previously configured the instrument to clear the enable register using the *PSC 1 command. Note that the enable register will not be cleared at power-on if you have configured the instrument using the *PSC 0 command.

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