Common Commands Introduction to Programming
Agilent 8163A/B, 8164A/B & 8166A/B Mainframes, Fifth Edition 31
Common Status Information
There are three registers for the status information. Two of these are 
status-registers and one is an enable-registers. These registers conform to 
the IEEE Standard 488.2-1987. You can find further descriptions of these 
registers under 
*ESE, *ESR?, and *STB?.
Figure 2  shows how the Standard Event Status Enable Mask (SESEM) 
and the Standard Event Status Register (SESR) determine the Event Status 
Bit (ESB) of the Status Byte.
Figure 2 The Event Status Bit
The SESR contains the information about events that are not slot specific. 
For details of the function of each bit of the SESR, see “Standard Event 
Status Register” on page 37.
The SESEM allows you to choose the event that may affect the ESB of the 
Status Byte. If you set a bit of the SESEM to zero, the corresponding event 
cannot affect the ESB. The default is for all the bits of the SESEM to be set 
to 0.
The questionable and operation status systems set the Operational Status 
Bit (OSB) and the Questionable Status Bit (QSB). These status systems 
are described in “The Status Model” on page 33 and “Status Reporting – 
The STATus Subsystem” on page 64.
01234567
*STB? returns the Status Byte Register 
Status 
OSB ESB QSB
*ESR? returns the Standard Event Status Register
001
01234567
Event 
100000
Status 
Register
01234567
Event 
111111
Status 
Enable
Mask
*ESE sets the Standard Event Status Enable Mask
&
&
&
&
&
&
&
&
OR
Byte
All bits shown as  are unused 
0
MAV