Tektronix AFG2021 Programmer's Manual page 122

Status and Events
Status Registers
3-4
There are six types of status registers:
Status Byte Register (SBR), (See page 3-4, Status Byte Register (SBR).)
Standard Event Status Register (SESR), (See page 3-5, Standard Event Status
Register (SESR).)
Operation Condition Register (OCR), (See page 3-8, Operation Condition
Register (OCR).)
Operation Event Register (OEVR), (See page 3-7, Operation Event Register
(OEVR).)
Questionable Condition Register (QCR), (See page 3-8, Questionable
Condition Register (QCR).)
Questionable Event Register (QEVR), (See page 3-8, Questionable Event
Register (QEVR).)
Status Byte Register (SBR). The SBR is made up of 8 bits. Bits 4, 5 and 6 are
defined in accordance with IEEE Std 488.2-1992, shown in the following figure.
These bits are used to monitor the output queue, SESR, and service requests,
respectively.
Figure 3-2: The Status Byte Register (SBR)
Table 3-1: SBR bit functions
Bit
7 (MSB)
6
AFG2021 Arbitrary Function Generator Programmer Manual
Function
OSB
RQS
Operation Status Bit.
Indicates that an operation
event has occurred.
Request Service. When
the instrument is accessed
using the GPIB serial poll
command, this bit is called
the Request Service (RQS)
bit and indicates to the
controller that a service
request has occurred (in
other words, that the GPIB
bus SRQ line is LOW). The
RQS bit is cleared when
serial poll ends.