R&S 1129.7246.03, Operating Manual

Page: 427 / 855

R&S ESU Remote Control – Basics
Status Reporting System
5.22 Operating Manual 1302.6163.12 - 03
5.7.3 Description of the Status Registers
5.7.3.1 Status Byte (STB) and Service Request Enable Register (SRE)
The STB is already defined in IEEE 488.2. It provides a rough overview of the instru-
ment status by collecting the pieces of information of the lower registers. It can thus
be compared with the CONDition part of an SCPI register and assumes the highest
level within the SCPI hierarchy. A special feature is that bit 6 acts as the sum bit of
the remaining bits of the status byte.
The STATUS BYTE is read out using the command "*STB?" or a serial poll.
The STB implies the SRE. It corresponds to the ENABle part of the SCPI registers
as to its function. 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 on the GPIB, which triggers an interrupt
in the controller if this is appropriately configured and can be further processed
there.
The SRE can be set using command "*SRE" and read using "*SRE?".
Bit
No. Meaning
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 message. This procedure is to be recommended since it
considerably reduces the problems involved with GPIB control.
3 QUEStionable status sum 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 specified in greater detail
by polling the QUEStionable status register.
4 MAV bit (message available)
The bit is set if a message is available in the output buffer which can be read.
This bit can be used to enable data to be automatically read from the instrument to the
controller (cf. chapter
“Remote Control – Programming Examples” ).
5 ESB bit
Sum bit of the event status register. It is set if one of the bits in the event status register is set
and enabled in the event status enable register.
Setting of this bit implies an error or an event which can be specified in greater detail by polling
the event status register.
6 MSS bit (master status summary bit)
The bit is set if the instrument triggers a service request. This is the case if one of the other
bits of this registers is set together with its mask bit in the service request enable register SRE.
7 OPERation status register sum bit
The bit is set if an EVENt bit is set in the OPERation-Status register and the associated
ENABle bit is set to 1.
A set bit indicates that the instrument is just performing an action. The type of action can be
determined by polling the OPERation-status register.