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Model DRC-93c
section
v
5 . 7 . 1
Monitor Voltage, Display
If the correct curve is selected,
Voltage or Resistance
but the display in temperature is
still incorrect, then check the
The display reading in volts or
data in the curve.
This can be
resistance should match the monitor
done over the IEEE by using the
reading and the voltage across the
test
program
and
the
XDN1N2
sensor, except for the 9215, 9305,
command.
9317C and 9318C input cards and the
-6
configuration.
If the readings
5 . 7 . 3
T h e
Heater Circuit
do not match then the input card
should be calibrated. If the moni-
If the DRC-93C does not have output
tor reading is incorrect and can
power check to see that U13 on
not be adjusted then the following
Figure 93C-1C
(the IM317HVK) is
IC's may need to be replaced.
tightly screwed into its heat sink.
It is on standoffs near the fan in
"Old" Input cards
the left rear of the unit.
1 .
8210, 8211 cards
-
replace U5
2.
8219,
8220
cards
-
replace U5.
Configure the DRC-93C as in Section
If
that
does
not
solve
the
5.5.6.2.
Verify
that there is
problem then replace U4.
heater current going to the load
"New" Input Cards
resistor.
1 .
9210,
9220
cards
-
replace U5
2 . For the 9318C, the monitor volt-
Next, measure the analog out signal
age
should
be
approximately
to be sure the PID circuits are
±10mV.
If it is not between 5-
operating correctly.
The analog
16mV then U16, U13 or U10 could
out signal can be measured at TP28
be bad.
For the 9317C the moni-
(Gnd at TP1).
If this is a posi-
tor voltage should be approxi-
tive value that varies from 0-7.3
mately a factor of ten lower.
volts as the gain setpoint, or
The
same
three
IC's
are
reset values are changed then the
involved.
circuit is probably operating cor-
rectly.
Now measure the voltage
If the monitor voltage is incor-
across from TP19 to TP21.
The
rect, the input card may control at
voltage should vary from
0
to
1
an offset or not at all.
volt as the analog out signal var-
ies from
0
to 7.3 volts.
As the
If the sensor voltage matches the
gain or manual heater is increased
monitor voltage and the display
the analog signal will increase and
voltage is incorrect then the A/D
the voltage between TP19 and TP21
needs to be calibrated.
will in-crease.
If the voltage
stays at
0
Volts then U45 or U46 is
5 . 7 . 2
Units
Display
is
correct
but
probably bad as long as the raw
temperature
reading
i s
incorrect
V+(TP21
to TP6)
is
close to 28
volts
for the 10-25
Ohm
Heater
If the units display matches the
Range (37 and 53 volts for the
25-
voltage or resistance value of the
35
and
35-50 Ohm Heater Ranges
sensor, but the temperature display
respectively).
The
V+
can be
is incorrect then check the curve
checked by measuring approximately
selected. This can be accomplished
28V from TP21 to TP1.
The V+ value
by holding down the
CURVE#
button
is
50
Volts if a W50 watt option is
or by reading the selected curve
installed in a DRC-91C or if the
over the interface using the W1
resistor setting is 50 ohms on the
command.
DRC-93C.
If a
W60
Watt option is
COPYRIGHT
3/88
5-7
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