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Model
DRc-91C/93C
9305
Thermocouple Input Card
Secondary sensor information
is
updated once every
25
cycles.
9 3 0 5 . 9 . 2
Control Amplifier
and
Rear
Panel
Offset
Adjustment
calibration
4 .
Locate the
Secondary Sensor
current
sensing
resistor
1 .
With the front panel of the
terminals
(I+ and
I-), the
i n s t r u m e n t ,
select
the
Secondary
current
source
thermocouple input and place in
adjustment
(10µ)
,
the Control
the V (voltage) units.
Amplifier Span adjustment (CNT
V), and the A/D converter span
2a. On
t h e
DRC-91C
disable
adjustment
(A/D)
on
the
Reference Junction Compensation
calibration cover for the 9305
by opening
(0)
switch
3
of the
Card.
appropriate SENSOR ID on the
rear of the instrument.
See
Adjustment
on
the
Terminal
Block.
2b. On
t h e
DRC-93C
disable
Reference Junction Compensation
6 .
Locate the test points
TP24
by using the
SENSOR,
SCAN
(t
,
(CNT V) and
TPl
(GND(2s)) of
and
A,
or
keys.
The Display
the Calibration Card.
should
show
-9305
when
the
SENSOR key is pressed.
See
during calibration because they
do not make good electrical
3 .
Connect the DVM plus and minus
connections.
Attach
test
leads to the
TP24 (CNT
V) and
equipment lead wires with the
TPl
(GND(2s))
found
on
the
terminal screws.
calibration
card
of
the
5.
Locate the Rear Panel Offset
Section 9305.7.2.
7. Avoid
using
clip
on
leads
Section 9305.7.3.
controller.
The
calibration
procedure
is
divided into three parts.
4 .
Apply a zero signal to the +V
and
-V
Thermocouple
Input
1 .
Calibration of the Secondary
terminals by
shorting across
Sensor Current Source.
the Terminal Block with a short
jumper
wire.
Allow
the
2.
Calibration
of
the
Control
Terminal Block temperature to
Signal Amplifier and Rear Panel
settle for five minutes.
Offset Adjustment.
5 .
Adjust the Rear Panel Offset
3.
Calibration of the Thermocouple
Adjustment
on
the
Terminal
and
Secondary
Sensor
A/D
Block until the output on the
converters
on
the
9305
DVM is
0.0000
volt.
Be sure to
Thermocouple card.
remove the jumper wire after
this step.
9 3 0 5 . 9 . 1
secondary Sensor
Current
Source calibration
6 .
Apply a
+10
millivolt signal to
the
+V
and
-V
Thermocouple
1 .
Connect the DVM plus lead to
Input terminals on the Terminal
terminal I+ and the DVM minus
B l o c k
a n d
a l l o w
t h e
lead to the I- terminal.
temperature to settle.
2 .
Adjust
the
trimpot
labelled
7.
The DVM should read about
-2
10µA so that the DVM reads
volts.
Adjust the input card
1.000
volt
±0.001
volt.
trimpot labeled
CNT
V (Control
COPYRIGHT
6/88
LSCI
9305-9
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