Manual
16
Model 835-M Programmer’s
Manual
V1.1 2011
Transition
Filter
The transition filter
is
a
special register
that
specifies
which types of bit state
changes
in
the
condition
register
will set
corresponding
bits in the event
register.
Negative transition filters
(NTR)
are
used
to
detect
condition changes
from True
(1)
to
False
(0);
positive
transition filters
(PTR)
are
used
to detect
c
o
ndition
changes
from
False
(0) to True
(1).
Setting both positive and negative filters True allows an
event to be reported anytime the
condition changes.
Transition filters are read-write.
Transition
filters
are
unaffe
c
ted
by
queries
or
*CLS (clear status)
and *RST
commands.
The
command
:STATus:PRESet sets
all
negative transition filters to all 0’s and
sets
all
positive
transition filters to all
1’s.
Event Register
The event register
latches
transition events from the
condition register as specified
by
t
he
transition
filter.
Bits
in the event register are
latched,
and
once
set they remain set until cleared by a query or a
*CLS command
Event
registers
are read only.
Enable
Register
The enable
register specifies
the bits in the event
register
that
can produce
a
summary
bit. The
Model
835-M
logically ANDs corresponding
bits in the event and enable
registers,
and
ORs
all
the
resulting
bits to obtain a
summary
bit.
Summary
bits are
recorded
in the
Summary Status
Byte.
Enable registers
are read-write. Querying an enable
register does
not affect it. The command
:STATus:PRESet sets
the Operation
Status Enable
register and the
Questionable Status
E
nable
register
to all 0’s.
Status Group
Reporting
The state of certain
Model
835-M
hardware and operational events and
condition
s
can
be
det
ermined
by
programming the
status system.
Three lower
status groups
provide
status
information to
the
Summary Status
Byte group. The
Summary
Statu
s
Byte group
is used
to determine the general nature of
an event or
condition
and the other
statu
s
groups
are
used
to determine the specific nature of the
event or condition.
Summary Status
Byte Group
The
Summary Status
Byte group,
consisting
of the
Summary Status
Byte
Enable
register and
the
Summary Status
Byte,
is used
to determine the general nature of an
Model
835-M
event or condition.
The bits in the
Summary Status
Byte provide the
f
ollowing:
Operation
Status
Group