High Speed Readings; Spec Readout, Test And Input Zero - Datron 1061A User Handbook Manual

High speed readings
Superfast
(1061)
Two
superfast
modes
are available,
SI
reducing the
full
range
measurement time
to
approx lOmS.
The
data
both on display
and output
is
reduced
to
4
l
A
digit
with
all
output
modes
available. In
S2
mode
each
full
range
measurement
takes
approx
5mS
the
display
being replaced
by
the
message
SF2 and
the
output
available
only
in
binary format
(02 or
03
modes).
Superfast excludes
the
use of autorange,
ratio,
dB,
maths
modes
and
max-min
(N3)
mode.
Programming
S0
will
place
the
instrument into
normal
operating mode.
Recommendations
for
the
use
of
superfast
modes
To
achieve the
high read rates available in
superfast
(SI
up
to
100/110 readings/second, S2
up
to 200/
220 readings/second
at
50/60Hz) and
to
output
these readings
over
the
bus
requires
some knowledge
of the controller's capabilities.
Responding
to
SRQ's
generated
by
the
DVM
at
the
end
of
each reading and then outputting
the
reading
as
an
ASCII
string
can
sometimes
introduce
intolerable
delays into the system.
For
example:-
the
response
to
SRQ's
in
some
controllers
can be
as
much
as 10
ms
and
the
subsequent output of a
14 byte
ASCII
string at
around
200^s per byte
limits
the
maximum
reading
speed
to
78 readings/ second.
This
problem can be overcome
by a
combination
of
techniques. Firstly,
to use a binary output
mode,
02
or
03
which
reduces the
number
of bytes
output
to four.
Secondly,
many
controllers
have
a fast
block
transfer
mode
of operation.
In this
mode,
bytes are continually accepted over
the
bus
as
they
become
available
(i.e.
as the
DVM
generates
new
readings)
and
are stored
in
a
temporary buffer.
When
the
block
transfer
is
complete,
the
data
may
be read out of the
buffer
and
processed as required.
The
DVM
requires
an
external
trigger
of
sufficient
frequency
(approximately 2kHz)
to
achieve
maximum
superfast speeds.
Spec
readout,
test
and
input zero
Spec.
The programming and execution of code El
causes
the
instrument
to
compute
the
measurement
uncertainty of
the
previous reading.
An SRQ
is
generated
(if
allowed) with the
status
byte indicating
a
normal
valid
measurement.
The
output format
is:
1.888E±88PUCrLf
(where
PU
=
per
unit)
The
DVM
will
be held
until
E0
is
programmed
or
until
a
GET
or
manual
trigger
is
received,
assuming
the correct trigger
mode
has
been
programmed.
Spec readout
is
not available for
maths
modes
or
when
in
binary output
mode.
Self
test.
When
the
DVM
receives
a
Y command
the internal
test
routine
is
initiated.
The
front panel
displays are not exercised in this test
and
only
option and calibration
memory
checks are included.
Any
error
will
be reported with the
generation of an
SRQ
together with the appropriate status
and an
error
message
made
available for
output.
A GET
or
manual
trigger (regardless
of trigger
mode
programmed)
will
continue the
test after
an
error
situation.
Upon
completion an appropriate pass
or
fail
status will
be generated with
an
SRQ,
and
the
DVM
will
return to the previously
programmed
range and
function.
Maths modes, max/min,
Av/dB
and
error
readout
will all
be
cleared
on
completion.
I
nput
Zero. Z
initiates
a
series
of
1
7
readings
at
an
internal
read
rate,
the
first
16 being
averaged and
the
result
used
as a
zero offset.
The
17th reading
is
available for output.
If
autorange
is
selected
each
range
is
zeroed
in
turn (lowest to highest).
Should
the offset
be too
large,
the store
is
not updated and
an
SRQ
and
error status
is
generated together with
an
error
message
for output.