Set Up Routine; Measurement Routine - Philips PM2521 Service Manual

31
1.4. 1.3.
Set
up
routine
The
set
up
routine
uses
the following subroutines:
Start-up
routine:
This routine checks
if
the
POWER ON
bit
is
set
and
if
so,
it
sets
the
relays for
the
internal calibration.
Refresh
routine:
This routine reads the function switch
until a function
is
located
an then updates the function
register.
Then
it
reads
the A-bus
switch, the automatic
bit,
the
LO
BAT
input
and
the
DATA HOLD
input.
It
also
checks
if
the function switch has been changed and
if
so,
it
makes
the necessary calibration measure-
ments.
Range
routine:
When
an
UP
or
DOWN
ranging button
is
depressed
a bit
is
set in
the range control status
register.
This routine
checks
this bit
and performs the
required
ranging.
Set
up
execution
routine:
This routine
shifts
the data
for the
relay settings in
the
D1908 (SAA1060)
and
also controls
the timing
for
shifting.
Check
routine:
The
check
routine
examines
the
Rdown
and
Rup
bits in
the range control
status
register.
If
the range
>
range max. then the instrument must
range
up.
If
the range
<
range min. then the instrument must
range
down.
It
also
ensures that
in
the
TRIGGER LEVEL
function only
manual
ranging
is
allowed.
1.4. 1.4.
Measurement
routine
The measurement
routine uses
the following subroutines:
ADC
measuring time
routine:
This routine
is
responsible for the whole
timing of the
ADC
(see
OQ0060
and OQ0064).
Counter measurement
routine:
The
frequency measurements
are
performed without
the
ADC.
This routine controls the
circuits
that
in
turn
control
the frequency
functions.
Timer
routine:
For timing measurements
in
position
s,
this
routine controls the timing functions.
It
checks for the
SET/RESET
pulse and the
STOP
bit.
BCD
conversion
routine:
The
value
counted
is
converted to
BCD
information
by
this routine.