Status Byte Register - Agilent Technologies 4155C Command Reference Manual

Figure 3-2

Status Byte Register

The Status Byte register contains bits related to the instrument's Status Byte (STB)
summary messages, Request Service (RQS) messages, and Master Summary Status
(MSS) messages. Refer to Figure 3-2 and Table 3-1.
Status Byte Register
The Status Byte Register can be read with either a serial poll or the *STB? common
query command (refer to Chapter 4).
Serial poll is a low-level GPIB command that can be executed by SPOLL in HP
BASIC, such as the following:
Status=SPOLL(@Hp4155)
Both serial poll and STB? read the Status Byte Register identically, but have
following difference:
• SPOLL returns RQS for bit6
• STB? returns MSS for bit6
RQS and MSS are always the same value, so returned Status Byte value is always
the same for these two methods.
In general, use serial polling (not *STB?) inside interrupt service routines. Use
*STB? in other cases (not in interrupt service routine) when you want to know the
value of Status Byte.
Agilent 4155C/4156C SCPI Command Reference, Edition 1
Status Reporting Structure
Status Byte Register
3-3