Rohde & Schwarz SMU200A - Contents of the Status Registers

Remote Control Basics
R&S
®
SMU200A
482Operating Manual 1007.9845.32 ─ 15
This part can be written into and read as required. Its contents are not affected by
reading.
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NTRansition
The Negative-TRansition part also acts as a transition filter. When a bit of the
CONDition part is changed from 1 to 0, the associated NTR bit decides whether the
EVENt bit is set to 1.
- NTR bit =1: the EVENt bit is set.
- NTR bit =0: the EVENt bit is not set.
This part can be written into and read as required. Its contents are not affected by
reading.
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EVENt
The EVENt part indicates whether an event has occurred since the last reading, it is
the "memory" of the condition part. It only indicates events passed on by the transition
filters. It is permanently updated by the instrument. This part can only be read by the
user. Reading the register clears it. This part is often equated with the entire register.
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ENABle
The ENABle part determines whether the associated EVENt bit contributes to the
sum bit (see below). Each bit of the EVENt part is "ANDed" with the associated
ENABle bit (symbol '&'). The results of all logical operations of this part are passed
on to the sum bit via an "OR" function (symbol '+').
ENABle bit = 0: the associated EVENt bit does not contribute to the sum bit
ENABle bit = 1: if the associated EVENt bit is "1", the sum bit is set to "1" as well.
This part can be written into and read by the user as required. Its contents are not
affected by reading.
Sum bit
The sum bit is obtained from the EVENt and ENABle part for each register. The result is
then entered into a bit of the CONDition part of the higher-order register.
The instrument automatically generates the sum bit for each register. Thus an event can
lead to a service request throughout all levels of the hierarchy.
6.5.3 Contents of the Status Registers
In the following sections, the contents of the status registers are described in more detail.
6.5.3.1 Status Byte (STB) and Service Request Enable Register (SRE)
The STatus Byte (STB) is already defined in IEEE 488.2. It provides a rough overview
of the instrument status by collecting the pieces of information of the lower registers. A
special feature is that bit 6 acts as the sum bit of the remaining bits of the status byte.
The STB is read using the command *STB or a serial poll.
The STatus Byte (STB) is linked to the Service Request Enable (SRE) register.
Each bit of the STB is assigned a bit in the SRE. Bit 6 of the SRE is ignored. If a bit is set
in the SRE and the associated bit in the STB changes from 0 to 1, a service request
Status Reporting System