Datron 4708 User Handbook Manual page 52

e.g.
Switch
setting
;
ADD
1
1010
=
ADDRESS
26
Table 5.3
Address
Selection
'ADD'
The
sixth
switch
is
provided
for possible future variants.
In the
4708, the position
of the
ADD
switch
is
immaterial, as the
normal bus addresses
can be
selected at either setting.
Addresses 0-30
With
an address selected in the
range 0
to
30
the
instrument
may
be
controlled
manually, or remotely as part
of a system
on
the
Bus.
The
address selected
must be
the
same
as
that
used
in the
controller
program
to activate the
4708.
N.B.
The
selected address
can be temporarily displayed
on
the
front
panel
when
in
manual
control,
by
touching
Error and
then
Guard.
Remote
Operation
When
the
4708
is
operating
under
the direction
of
the
controller,
the
legend
rem
appears
on
the
mode
display,
and
all
front panel
controls are disabled
except
Power.
On
entering,
any
earlier
(manual)
selection
of
Error
mode
is
cancelled.
During remote operation, the
facilities
of Error
mode
are
excluded, as they
can
easily
be
programmed
into the
controller.
Spec
mode
is
also cancelled,
but 'Spec' information
can
be obtained by bus
command.
There
is
no Spec
mode
display
on
the front
panel during
remote
operation.
The 4708
power-up sequence
is
performed
as for
manual
operation.
After
power-up, and on recovery
from
a
power
failure,
the
4708 generates an
SRQ
and prepares an
'RQS
Status Byte' for transmission to
the controller as
a response
to
its
subsequent serial
poll.
Calibration
Enable
A
'Calibration
Enable'
command
via the
bus
is
required
to set
the
instrument into
its
Remote
Calibration
mode
(the
CALI-
BRATION ENABLE
keyswitch
on
the rear panel
must
already
be
set at
ENABLE).
Selection
of any address
0-30
inhibits
manual
calibration
from
the front panel. In
remote,
calibration
may
be
initiated
with
any
address
in
range
0-30
selected.
Address
31
(Illegal
bus
address)
This address configures
manual
operation only, inhibiting
remote
facilities.
Address
31
must
be selected (with
CAL
key
set to
ENABLE),
for
manual
calibration to
be
carried
out.
Temporary Transfer
to
Local Operation (GTL)
The 4708 can be
programmed
to
switch into 'Local' operation
(Command GTL),
permitting a user
to
take
manual
control
from
the front panel.
The
system controllerregains
'Remote'
control
by sending
the
following overriding
commands:
LAD
With
REN
True
The
controller
addresses the
4708
as
a
listener
with the
Remote
Enable management
line true
(Low). This returns the
4708
from
local to
remote
control.
Any commands
which had been
sent
during the period
under
local control will
then
be
executed.
SDC
Specific
'Device Clear'
commands
are sent over the bus,
re-
turning the
4708
to
a predetermined
state
(described
later in this
section).
Programming
Instructions
Programming
Strings
From
the
example given
earlier in this
section
it is
evident
that
the
4708
requires
an
address
code followed
by
a
series
of
device-
dependent messages
or
commands
to alter
its
configuration.
5-4