871
SPECIFICATIONS
TEMPERATURE SENSOR: Type K
(NiCr-NiAI) thermocouple.
THERMOCOUPLE
INPUTS:
Two,
switch selected.
RANGES
GENERAL
DISPLAY:
3~-digit
LCD,
0.6"
height.
Polarity and decimal point indication.
CONVERSION PERIOD: 400ms (2.5
readings/sec).
OVERRANGE &OPEN-THERMO-
COUPLE
INDICATION:
3least signifi-
cant digits blanked.
MAXIMUM
COMMON
MODE
VOLTAGE':
500V peak
to
earth.
TC1 TO TC2
ISOLATION':
500V peak.
mV
OUTPUT: Non-linearized, cold-
junction compensated thermocouple
output. (Not isolated from selected
TC
input.)
ACCURACY:
±0.25%
of
reading
±1°C(0.25% ±1.8°F)
for
one year,
18
0to 28°C ambient. Includes N8S
conformity, cold junction compensation
and repeatability errors. Excludes ther-
mocouple errors, however, thermo-
couple errors around
OOC
may
be
comp-
ensated for by
an
internal
zero
adjust-
ment. Extended accuracy from -40°C
to
-55°C:
+2°/
-Ooc.
REPEATABILITY:
±0.2°C
typical for 1
hour at constant ambient temperature.
TEMPERATURE COEFFICIENT: 18° to
28°C; Included
in
accuracy specifica-
tion.
From
0°
to 18° and 28° to 50°C;
less
than ±(0.025%
of
reading
+O.l°CI/oC.
INPUT
CURRENT: 25nA typical; 50nA
maximum.
MAXIMUM
ALLOWABLE
TC
INPUT
OVERLOAD: 150V continuous, 300V
momentary
(10
seconds).
NORMAL
MODE
REJECTION RATIO:
Greater than 45dB at
50
&60Hz.
COMMON
MODE
REJECTION
RATIO: Greater than 120dB at
DC,
50
&60Hz.
'WARNING: Ashock hazard exists when
probes or sensors
are
exposed to voltage
levels greater than 30V rms or 42.4V
peak.
mV
OUTPUT
ACCURACY
(18°-28°C):
±40!'V
(OC
ranges);
±80!'V
(OF
ranges).
OOC
=
O.OmV.
Outputresistance:
17kO.
mV
OUTPUT
TEMPERATURE COEF-
FICIENT 10°_18°C &28°-500CI:
Less
than
(0.1
x-accuracy specification)/oC.
mV
OUTPUT
PROTECTION: 35V
DC
(42V peak) maximum; mV +
to
mV-
and selected TC input
to
mV +
or
mV-.
ENVIRONMENTAL
LIMITS
FOR
OPERATING:
0°
to
50°C,
less
than
80% relative humidity up
to
35°C,
linearly derate
3%R.H./°C
35°
to
50°C.
If
the instrument
has
been stored above
18°C
it
may typically
be
operated at
-10°C for
15
minutes.
ENVIRONMENTAL
LIMITS
FOR
STORAGE: -35°C to 60o
C,
less
than
90% relative humidity up
to
35°C;
linearly derate 3% R.H./oC 35° to
60°C.
COLD-JUNCTION
COMPENSATION:
Semiconductor temperature sensor.
THERMOCOUPLE
LINEARIZATION:
Multislope
A/D
with
11
piece-wise-
linear segments between -40°C and
13700
C.
INPUT
CONNECTIONS: Two, minia-
ture TC connectors.
mV
OUTPUT
CONNECTION: Dual
banana jacks.
POWER:
9V
alkaline or carbon-zinc
(NEDA 1604) battery.
BATTERY LIFE (CONTINUOUS): 100
hours typical with alkaline battery;
50
hours typical with carbon-zinc battery.
BATTERY
INDICATOR:
Display indi-
cates
"BAT"
when
less
than 10%
of
life
remains.
DIMENSIONS.
WEIGHT: 178mm long
x78mm wide x42mm thick (7.0" x
3.1"
x1.6"). Net weight 300gm
(10.60z).
ACCESSORIES SUPPLIED: Battery,
manual, Model 8712 Thermocouple
Sensor.
-40.0 to 199.9°C O.l°C
-40
to
1370°C
l°C
Temperature
Span
Resolution
-40.0
to
199.9°F O.l°F
-40
to 1999°F 1°F
Ranges
WARRANTY
SERVICE POLICY
SAFETY
SYMBOLS
AND
TERMS
The symbol
~
on the instrument denotes that the user should refer
to the operating instructions.
The symbol
#on
the instrument denotes that up
to
500V may
be
present on the terminal(s).
The
WARNING
used
in
this manual explains dangers that could result
in
personal injury or death.
The
CAUTION
used
in this manual explains
hazards
that could damage
the instrument.
For
service on your Model
871
Digital Thermometer, contact your local
Keithley representative
who
will
be
able to give you immediate
assistance in most
cases.
Complete repair
and
calibration facilities
are
maintained in the United States, West Germany, Great Britain,
France,
the Netherlands, Switzerland, and Austria. Information concerning the
application, operation or service
of
your instrument may
be
directed to
the applications engineer at any
of
the above locations. (Addresses
are
located on the back cover.)
We warrant
each
of
our products
to
be
free from defects
in
material
and
workmanship. Our obligation under this warranty
is
to repair or replace,
at our option, any instrument or part thereof which, within a
year
from
date
of
shipment, proves defective upon examination.
We
will
pay
local
domestic surface freight costs. (NOTE: This warranty does not cover
battery replacement or damage due to battery leakage.)
