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9305
Thermocouple
Input
C a r d
calculated above is applied to the
Setpoint D/A to obtain the Setpoint
voltage for control.
The
control
analog
hardware
compares the Setpoint voltage from
the Setpoint D/A converter and the
amplified thermocouple voltage to
obtain an error signal.
The error
signal is minimized through the PID
control circuitry.
9305.7
OpeRATING
INSTRUCTIONS
9 3 0 5 . 7 . 1
Thermocouple
C u r v e
Selection
Thermocouple Tables are chosen by
selecting one of the Curves numbers
given
in
Table
9305-3.
The
instruments detect the presence of
the Thermocouple Input Card and
then select the proper Thermocouple
Table rather
than the Standard
Diode or Resistance curve listed in
the Instruction Manual.
The SENSOR ID Switches on the rear
panel of the DRC-91C are used to
select
curves
as
described
in
Instruction Manual Section
2.3.8.
Curve selection can also be made
over
Computer
Interface
as
described in Section 4.8.5.
On the DRC-93C
the Thermocouple
Table is selected by selecting the
Curve # as described
in
the DRC-93C
Instruction Manual Section
3.9.1.
Curve selection can also be made
over
Computer
Interface
as
described in Section
4 . 8 . 9 .
9305.7.2
selection of Reference
Junction COmpensation on
the
DRC-91c
Whether or not Reference Junction
Compensation is used is selected
using Switch 3 of the SENSOR ID.
When Switch
3
of the SENSOR ID is
closed
(1)
the Reference Junction
9305-6
M o d e l
DRC-91C/93C
C o m p e n s a t e d
value
of
t h e
thermocouple voltage is displayed.
When Switch 3 of the SENSOR ID is
open
(0),
the actual
(measured)
t h e r m o c o u p l e
v o l t a g e
o r
uncompensated
temperature
is
displayed.
With the
9305
selected
as the Display Sensor, hold the
LOCAL
key to show card type and
curve number.
If compensation is
active the display will show
+9305
and if it
is
inactive -9305.
Table
9305-3.
Curve
Numbers
Thermocouple
Type
Chrome1 vs.
Au-0.07 at.% Fe
Chromel vs.
Au-0.03 at.% Fe
E
K
T
standard
Curve #
00
01
02
03
04
9305.7.3
Selection
of
Reference
Junction Compensation on the
DRc-93c
When
a
9305
Thermocouple
Input
Cards is installed, pressing the
SENSOR key
will
display either
+9305
or
-9305.
The
+9305
means
that the thermocouple voltage is
corrected for the Terminal Block
temperature.
The
-9305
means that
the thermocouple voltage is being
displayed with no compensation.
To
select
whether
Reference
Junction Compensation is used or
not is accomplished from the front
panel
by
a
combination of
the
SENSOR key, SCAN
key and the
key and
key.
The procedure
is as follows.
COPYRIGHT 6/88
LSCI
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