Datron 1062 - Page 24

16
Option
checked
ID
line low
Pin No.
of M19
held low
if
Option
incorporated
AC
ID
1
M19-3
12
ID
2
M19-1
1
I
ID
3
Ml
9-4
RATIO
V
ID 4
M19-10
^
Fig. 3.2
POWER-ON
OPTIONS
FITTED
TEST
high on Ml 8-4,
turning
the opto-isolator
M2-B on
and thus
COND.
VAL (M2-8)
is
high,
signalling to
the
Digital
assembly that
the AC
option is fitted.
Similarly, when
the
12,
I
or RATIO
options
are interrogated,
the
appropriate
output
of M19
is set low
if the
option is
fitted causing the
COND. VAL to
be set
high.
*Note:
ID
and lA
lines
logic
'1'
=
-1-5
volts
logic
'0'
5
0
volts
AD
lines
logic
'1'=
0
volts
logic
'0'
5
-15
volts
The next step
in the
power-up
sequence as
far as
the
analog
circuits are
concerned, is to
be
placed
into the DC,
1000V
range
(See
Fig. 3.3
Flowchart).
Firstly,
all
assemblies
are
deselected by
placing
logic '1's on
all the
ID
lines,
then
setting
the IA0
and IA1
lines
low (see
Fig.
3.4),
clocking
the
option
selects
latches (M20
Analog
assembly, M5
AC
assembly, M9
Ohms
assembly.
Ml Ratio
assembly
from M17-3.
Both lA
lines
then
return
high.