Remote Interface Reference 3
SCPI Status Registers
E364xA User’s and Service Guide 107
SCPI Status Registers
All SCPI instruments implement status registers in the same
way. The status system records various instrument
conditions in three register groups: the Status Byte register,
the Standard Event register, and the Questionable Status
register groups. The Status Byte register records high- level
summary information reported in the other register groups.
The diagram on the subsequent pages illustrates the SCPI
status system used by the power supply.
What is an event register?
An event register is a read- only register that reports defined
conditions within the power supply. Bits in an event register
are latched. Once an event bit is set, subsequent state
changes are ignored. Bits in an event register are
automatically cleared by a query of that register (such as
*ESR? or STAT:QUES:EVEN?) or by sending the *CLS (clear
status) command. A reset (*RST) or device clear will not
clear bits in event registers. Querying an event register
returns a decimal value which corresponds to the
binary- weighted sum of all bits set in the register.
What is an enable register?
An enable register defines which bits in the corresponding
event register are logically ORed together to form a single
summary bit. Enable registers are both readable and
writable. Querying an enable register will not clear it. The
*CLS (clear status) command does not clear enable registers
but it does clear the bits in the event registers. To enable
bits in an enable register, you must write a decimal value
which corresponds to the binary- weighted sum of the bits
you wish to enable in the register.
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