RADIOMETER TCM3 - Page 25

TCM3 and TCM30 Service Manual
2. TCM3
Checkout
and
Adjustment,
Continued
pCO, Channel
Step 0:11
Temperature
Channel 1
Step 0:12
Step 0:14
199808-1
This
procedure
checks
the
zero-point
and
gain
for
the
pCO,
channel.
Step Action
1.
Connect
the
simulator
TEST
SOURCE
+1
mV
terminal
to
the
TEST
INPUT
pCO;
terminal
and
check
that
the
pCO,
display
shows
01.0
+
01.0
(1.0
+
1.0
mV).
If
necessary,
adjust
R88
(TCM3
RUN
22
onwards
only)
on
the
Analog
PCB
to 1.0 + 1.0
mV.
Note the deviation.
Connect
the
simulator
TEST
SOURCE
+
185
mV
terminal
to
the
TEST
INPUT
pCO,
terminal
and
check
that
the
pCO/pO,
display
reading
is
0.1
85.0.
The
deviation
must
be
less
than
+
0.0
00.5_when
compensated
for the
zero-point
error.
Example:
The
pCO,
zero
point
error
is
measured
to
be
0.2
mV.
The
gain
value
then
must
be
between
184.7
and
185.7
mV.
This
procedure
checks
the
zero-point
and
gain
for
the
temperature
channel
1.
The
procedures
require
the
cabinet
to
be
opened.
Step Action
1.
3.
4.
Set
the
simulator
TEMPERATURE
switch
to
37
°C
and
the
THERMISTOR
switch
to
SINGLE
.
Check
that
the
display
shows
36.985
and
37.015
(zero-point).
If
outside,
adjust
R17
on
the
Analog
PCB
to
a
reading
between
36.997
and
37.003.
Set the simulator TEMPERATURE switch to 45 °C.
Check
that
the
display
reading
is
between
44
985
and
45
015
(gain).
If
outside,
adjust
R20
on
the
Analog
PCB
to
a
reading
between
44
995
and
45
005.
Readjust R17 and R20.
Set the simulator TEMPERATURE switch to 37 °C.
Check
that
the
display
reading
is
between
36
900
and
37
100.
Set the simulator TEMPERATURE switch to 45 °C.
Check that the display reading is between 44 900 and 45 100
(thermistor 1 via the MUX).
Continued on next page
2-19