Reference Information for Remote Control
R&S
®
SMA100B
524
User Manual 1178.3834.02 ─ 03
read by the user. Reading the register clears it. This part is often equated with the
entire register.
●
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.
A.1.5.3
Status Byte (STB) and Service Request Enable Register (SRE)
The
STatus Byte
(STB) is already defined in IEEE 488.2. It provides a rough over-
view of the instrument status by collecting the pieces of information of the lower regis-
ters. 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
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 (SRQ) is generated. The SRE can be set using the command
and read
using the command
*SRE?
.
Table A-5: Meaning of the bits used in the status byte
Bit No.
Meaning
0...1
Not used
2
Error Queue not empty
The bit is set when an entry is made in the error queue. If this bit is enabled by the SRE, each
entry of the error queue generates a service request. Thus an error can be recognized and
specified in greater detail by polling the error queue. The poll provides an informative error mes-
sage. This procedure is to be recommended since it considerably reduces the problems
involved with remote control.
3
QUEStionable status register summary bit
The bit is set if an
EVENt
bit is set in the
QUEStionable
status register and the associated
ENABle
bit is set to 1. A set bit indicates a questionable instrument status, which can be speci-
fied in greater detail by querying the
STATus:QUEStionable
status register.
Additional Basics on Remote Control
