Philips pm2521 - Set up Routine; Measurement Routine

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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.