User manual

Remote Control
R&S
®
RTO
416User Manual 1316.0827.02 ─ 06
Query of an instrument status
Each part of any status register can be read using queries. There are two types of com-
mands:
●
The common commands *ESR?, *IDN?, *IST?, *STB? query the higher-level reg-
isters.
●
The commands of the STATus system query the SCPI registers
(STATus:QUEStionable...)
The returned value is always a decimal number that represents the bit pattern of the
queried register. This number is evaluated by the controller program.
Queries are usually used after an SRQ in order to obtain more detailed information on
the cause of the SRQ.
Decimal representation of a bit pattern
The STB and ESR registers contain 8 bits, the SCPI registers 16 bits. The contents of a
status register are specified and transferred as a single decimal number. To make this
possible, each bit is assigned a weighted value. The decimal number is calculated as the
sum of the weighted values of all bits in the register that are set to 1.
Example:
The decimal value 40 = 32 + 8 indicates that bits no. 3 and 5 in the status register (e.g.
the QUEStionable status summary bit and the ESB bit in the STatus Byte ) are set.
Error Queue
Each error state in the instrument leads to an entry in the error queue. The entries of the
error queue are detailed plain text error messages that can be looked up in the Error Log
or queried via remote control using SYSTem:ERRor[:NEXT]? or
SYSTem:ERRor:ALL?. Each call of SYSTem:ERRor[:NEXT]? provides one entry from
the error queue. If no error messages are stored there any more, the instrument responds
with 0, "No error".
The error queue should be queried after every SRQ in the controller program as the
entries describe the cause of an error more precisely than the status registers. Especially
in the test phase of a controller program the error queue should be queried regularly since
faulty commands from the controller to the instrument are recorded there as well.
16.1.6.5 Reset Values of the Status Reporting System
The following table contains the different commands and events causing the status
reporting system to be reset. None of the commands, except *RST and
Basics