This section describes the structure of the SCPI status system used by the M8190A.
The status system records various conditions and states of the instrument in several
register groups as shown on the following pages. Each of the register groups is made
up of several low level registers called Condition registers, Event registers, and
Enable registers which control the action of specific bits within the register group.
These groups are explained below:
A condition register continuously monitors the state of the instrument. The bits
in the condition register are updated in real time and the bits are not latched or
buffered. This is a read-only register and bits are not cleared when you read the
register. A query of a condition register returns a decimal value which
corresponds to the binary-weighted sum of all bits set in that register.
An event register latches the various events from changes in the condition
register. There is no buffering in this register; while an event bit is set,
subsequent events corresponding to that bit are ignored. This is a read only
register. Once a bit is set, it remains set until cleared by query command (such
as STAT:QUES:EVEN?) or a *CLS (clear status) command. A query of
this register returns a decimal value which corresponds to the binary-weighted
sum of all bits set in that register.
An enable register defines which bits in the event register will be reported to the
Status Byte register group. You can write to or read from an enable register. A
*CLS (clear status) command will not clear the enable register but it does
clear all bits in the event register. A STAT:PRES command clears all bits in
the enable register. To enable bits in the enable register to be reported to the
Status Byte register, you must write a decimal value which corresponds to the
binary weighted sum of the corresponding bits.
Transition Filters are used to detect changes of the state in the condition
register and set the corresponding bit in the event register. You can set
transition filter bits to detect positive transitions (PTR), negative transitions
(NTR) or both. Transition filters are read/write registers. They are not affected by
*CLS.
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