Fluke 8508A User manual

8508A Reference Multimeter
Extended Specifications

2Fluke Corporation 8508A Extended Specifications
Introduction
The Fluke 8508A has been designed specifically
for metrologists. Not only does it provide the
performance metrologists need, but it is specified
in a way to allow users to really understand the
uncertainties of the measurements, and easily
make allowance for those uncertainty contribu-
tions when performing measurement uncertainty
analyses and compiling uncertainty budgets.
Contemporary metrology practices, including
ISO 17025 based laboratory accreditation
schemes, require uncertainty analysis to be
performed in accordance with the statistically
based techniques described in the ISO Guide to
the Expression of Uncertainty in Measurement
(often referred to as the 'GUM'). For convenience,
the 8508A specifications are quoted at a coverage
factor of k=2, equivalent to a confidence level of
approximately 95 %, as required by these
methods. Specifications are also provided at a
confidence level of 99 %.
Performance specifications for the 8508A
consist of two elements; the first is a contribution
expressed as parts-per-million of the Reading,
and the second contribution is expressed as
parts-per-million of the Range. These must be
evaluated and combined for the relevant reading
and range values applicable to the measurement
being made, ensuring that both elements are
evaluated on the same basis, such as parts per
million of the measured value or in absolute
terms (volts, amps, ohms, etc). The two elements
are combined by adding algebraically. For
example, measuring 10 V on the 20 VDC range
and applying the 365 day ±1 °C specifications:
First, expressing the contributions in terms of
parts-per-million of the measured value.
Second, expressing the contributions in volts:
The 8508A is designed to provide accuracy
and stability without the need for internal auto
or self calibration routines which may otherwise
compromise the continuity and traceability of
measurement performance history.
To realize the full potential of the 8508A per-
formance, accepted metrology practices should
be employed, such as performing a zeroing or
null operation to remove any offsets present in
the measurement setup when making DC meas-
urements. The 8508A specifications assume that
these methods are employed.
Absolute and Relative specifications
The Relative to Calibration Standards specifica-
tions describe the performance of the 8508A
itself for the time periods and temperature range
listed, excluding the uncertainty of the standards
used to perform calibration of the 8508A during
manufacture. The Absolute specifications
include the uncertainty of the standards used to
perform calibration of the 8508A at manufacture
and may be used to determine the uncertainty
of measurements made with the 8508A for
periods up to 1 year and over a temperature
range of ±5 °C from calibration. If the user has
their 8508A calibrated with different uncertainties,
the Relative specifications can be combined
with the uncertainties applicable to that
calibration to determine the effective absolute
uncertainty following that calibration.
Applying user’s calibration uncertainties
When the 8508A is calibrated by another
laboratory, the uncertainties of the calibration
standards used may be applied by combining
those uncertainties with the 8508A's Relative to
Standards specifications. The applicable
calibration uncertainties and the 8508A relative
specifications must both be expressed at the
same confidence level, and be combined in an
RSS (Root Sum Square) summation. Accepted
metrology practice mandates that calibration
uncertainties are stated at 95 %. Check the
applicable calibration uncertainties are stated at
95 % and then combine them with the 8508A
95 % Relative specifications. For example, if the
8508A is calibrated at 10 VDC with an
uncertainty of 1.5 ppm at 95 % the absolute
uncertainty at 10 V for a period of 90 days and
±1 °C from calibration is:
Interpreting and applying
the specifications

Fluke Corporation 8508A Extended Specifications 3
Operating and calibration
temperature ranges
As a metrology tool, the 8508A will commonly
be used in a calibration laboratory where the
temperature would be controlled to ±1 °C, and
the 8508A ±1 °C specifications are applicable to
those situations. The majority of electrical
calibration laboratories operate at a nominal
temperature of 23 °C, the temperature at which
the 8508A is calibrated by Fluke during manu-
facture and service. The 8508A is also capable
of being calibrated at any temperature between
20 °C and 25 °C and the ±1 °C specifications will
apply to operation within ±1 °C of that calibra-
tion temperature. In the 8508A specification
tables, the temperature of calibration is referred
to as TCal. Specifications for ±5 °C are provided
for situations where the 8508A is operated in
environments with wider temperature variations
up to ±5 °C. For applications where the knowledge
of the effect of temperature on 8508A perform-
ance is important, temperature coefficients are
listed in the 8508A specifications. If the operating
temperature is within the range 15 °C to 30 °C,
the 15 °C to 30 °C temperature coefficient
specifications are applicable; otherwise use the
5 °C to 15 °C/30 °C to 40 °C figures, provided
the temperature lies within that range. The
8508A may be operated at temperatures
between 0 °C and 50 °C, but performance is not
specified outside the range 5 °C to 40 °C.
Applying temperature coefficient
specifications
The 8508A specification tables include
information for the typical operating conditions
of ±1 °C for calibration laboratories with tight
temperature control, and ±5 °C for calibration
laboratories with looser temperature control or
uncontrolled environments within that tempera-
ture range. For the majority of applications,
choosing the Absolute specifications for the most
appropriate operating temperature range will be
adequate. However performance at other
temperatures may be determined by including
an allowance for temperature coefficient over
the additional temperature range. Care should
be taken when making this calculation, as an
amount of temperature coefficient is already
included in the 8508A specifications, and those
specifications are themselves based on combining
contributions using techniques similar to those
employed in uncertainty analysis. For example,
consider operating at 33 °C, 10 °C from the 23 °C
calibration temperature. The ±5 °C specifications
already include a contribution for 5 °C of tem-
perature difference, so this amount of temperature
effect must be removed before the effect of the
10 °C difference is added. Consider 10 V on the
20 VDC range: 365 day absolute specification
(95 %) at 33 °C expressed in parts-per-million of
10 V is:
Applying the specifications
The Fluke 8508A and 8508A-SPRT Standard
Platinum Resistance Thermometer

Ratio measurements
The 8508A Ratio mode will automatically take
measurements of inputs applied to the front and
rear terminals and display the result as a ratio in
the voltage and resistance functions. The
measurements can be made on the same range
or different ranges. When making measurements
on different ranges, the error in each measure-
ment is evaluated by applying the relevant
specification for each range and combining the
two specifications in an RSS summation,
expressing the contributions in parts-per-million
of the measured values. For example, making
measurements of the ratio of 100 mV on the
200 mVDC range and 100 V on the 200 VDC
range, applying the 365 day ±1 °C Absolute
specifications:
Making measurements on the same range
will eliminate range-to-range errors, such as
drift since the time of calibration, and improve
the result. When making measurements on the
same range, these errors will affect both meas-
urements and effectively cancel, leaving short
term noise and linearity as the dominant errors.
The 20 minute Transfer Uncertainty specifica-
tions are provided to describe the performance
obtained when making ratio measurements on
the same range. The error in each measurement
is evaluated by applying the relevant 20 minute
Transfer Uncertainty Specification for each value
and combining the two specifications in an RSS
summation, expressing the contributions in
parts-per-million of the measured values. If the
measurements are made within the same range,
but independently (not using the ratio mode)
with an elapsed time greater than 20 minutes
but less than 24 hours between the measurements,
then the 24 hour specifications should be
applied instead.
For example, making measurements of the
ratio of 5 V and 10 V on the 20 VDC range,
applying the 20 minute Transfer Uncertainty
Specifications:
Additional errors
The 8508A specifications are listed for the
maximum resolution in each function, using the
Normal reading mode. For measurements taken
in other resolutions or the Fast read mode
additional error contributions listed in the Read
Rate and Additional Uncertainty table must be
included. These additional contributions must be
added algebraically to the relevant specifica-
tions. For example, measuring 10 V on the
20 VDC range at 5 digit resolution in Fast mode
and applying the 365 day ±1 °C Absolute
specifications:
Other additional contributions apply in certain
situations and are also to be added algebraically
to the relevant specifications. These additional
contributions include the DC Accuracy specifica-
tion to be applied when making DC measure-
ments on the AC Voltage function when DC
coupled, and the High Voltage Adder when
making measurements above 300 V on the AC
function.
4Fluke Corporation 8508A Extended Specifications
Applying the specifications

Fluke Corporation 8508A Extended Specifications 5
Type Multi-slope, multi-cycle A-D Converter
CMRR (1 kΩunbalance) [5] 140 dB at DC and 1 - 60 Hz
NMRR [5]
Filter Out 60 dB at 50/60 Hz ±0.09 %
Filter In 110 dB at 50/60 Hz ±0.09 %
Protection (All ranges) 1 kV rms
Input Impedance
200 mV to 20 V Ranges >100 GΩ
200 V & 1000 V Ranges 10.1 MΩ± 1 %
Max Input Current 50 pA
Ratio Accuracy
Range to Range ±(Net Front Input Accuracy + Net Rear Input Accuracy)
Within Range Apply 24 hour or 20 minute Transfer
Uncertainty specifications
Settling Time (to 10 ppm step size)
Filter Out <50 ms
Filter In <1 s
DC Voltage [1] [2] [3]
Full Scale Uncertainty Relative to Cal Stds
24 hour
TCal ±1 °C
365 day
TCal ±1 °C
200 mV 199.999 999 0.7 + 0.5 1.4 + 0.5 2.7 + 0.5 4.5 + 0.5 5.0 + 0.5
2 V 1.999 999 99 0.5 + 0.2 1.4 + 0.2 2.7 + 0.2 3.0 + 0.2 3.5 + 0.2
20 V 19.999 999 9 0.5 + 0.2 1.4 + 0.2 2.7 + 0.2 3.0 + 0.2 3.5 + 0.2
200 V 199.999 999 1.0 + 0.2 2.6 + 0.2 4.0 + 0.2 4.5 + 0.2 5.5 + 0.2
1000 V 1050.000 00 1.0 + 0.5 2.6 + 0.5 4.0 + 0.5 4.5 + 0.5 5.5 + 0.5
200 mV 199.999 999 0.8 + 0.6 2.0 + 0.6 3.5 + 0.6 6.0 + 0.6 6.5 + 0.6
2 V 1.999 999 99 0.6+ 0.25 1.8 + 0.25 3.5 + 0.25 4.0 + 0.25 4.5 + 0.25
20 V 19.999 999 9 0.6 + 0.25 1.8 + 0.25 3.5 + 0.25 4.0 + 0.25 4.5 + 0.25
200 V 199.999 999 1.2 + 0.25 3.5 + 0.25 5.2 + 0.25 6.0 + 0.25 7.0 + 0.25
1000 V 1050.000 00 1.2 + 0.6 3.5 + 0.6 5.2 + 0.6 6.0 + 0.6 7.0 + 0.6
90 day
TCal ±1 °C
Range
365 day
TCal ±5 °C
95 % Confidence Level
99 % Confidence Level
DC Voltage (Secondary Specifications) [1] [2] [3]
Transfer
Uncertainty
20 mins ±1 °C
± (ppm Reading
+ ppm Range)
Temperature Coefficient
200 mV 0.4 + 0.3 0.4 0.6
2 V 0.12 + 0.1 0.3 0.5
20 V 0.12 + 0.1 0.3 0.5
200 V 0.4 + 0.1 0.7 1.0
1000 V 0.4 + 0.3 0.7 1.0
Range
± ppm Reading/°C
15 °C - 30 °C
5 °C - 15 °C
30 °C - 40 °C
DC Voltage specifications
365 day
TCal ±1 °C
±(ppm Reading + ppm Range) [4]
Absolute Uncertainties

6Fluke Corporation 8508A Extended Specifications
DC Current specifications
DC Current (Secondary Specifications) [1] [2] [3]
Input
Impedance
(Ω)
Temperature Coefficient
200 µA150 150 0.4 0.6
2 mA 15.2 15.2 0.4 0.6
20 mA 1.8 1.9 1.2 1.8
200 mA 1.2 1.3 6.0 9.0
2 A 0.3 0.4 8.0 12
20 A 0.04 -8.0 12
Range
± ppm Reading/°C
15 °C - 30 °C
5 °C - 15 °C
30 °C - 40 °C
Type Multi-slope, multi-cycle A-D Converter
Protection
Front Input 20 A rms
Rear Input 2 A rms, Rear Panel Fuse
Settling Time
200 µΑ to 200 mA Ranges, to 10 ppm step size Filter Out <50 ms, Filter In <1 s
2 A Range to 10 ppm step size <1 s
20 A Range to 100 ppm step size <30 s
DC Current [1] [2] [3]
Full Scale Uncertainty Relative to Cal Stds
24 hour
TCal ±1 °C
365 day
TCal ±1 °C
200 µA199.999 99 5.5 + 2.0 6.0 + 2.0 6.5 + 2.0 12 + 2.0 12 + 2.0
2 mA 1.999 999 9 5.5 + 2.0 6.0 + 2.0 6.5 + 2.0 12 + 2.0 12 + 2.0
20 mA 19.999 999 6.5 + 2.0 7.0 + 2.0 8.0 + 2.0 13 + 2.0 14 + 2.0
200 mA 199.999 99 28 + 4.0 30 + 4.0 33 + 4.0 36 + 4.0 48 + 4.0
2 A 1.999 999 9 80 + 8.0 125 + 8.0 170 + 8.0 170 + 8.0 185 + 8.0
20 A 19.999 999 200 + 20 290 + 20 380 + 20 380 + 20 400 + 20
200 µA199.999 99 7.0 + 2.0 7.5 + 2.0 8.0 + 2.0 15 + 2.0 16 + 2.0
2 mA 1.999 999 9 7.0 + 2.0 7.5 + 2.0 8.0 + 2.0 15 + 2.0 16 + 2.0
20 mA 19.999 999 8.0 + 2.0 9.0 + 2.0 10 + 2.0 16 + 2.0 18 + 2.0
200 mA 199.999 99 35 + 4.0 37 + 4.0 40 + 4.0 45 + 4.0 60 + 4.0
2 A 1.999 999 9 100 + 8.0 150 + 8.0 205 + 8.0 210 + 8.0 225 + 8.0
20 A 19.999 999 250 + 20 350 + 20 450 + 20 455 + 20 500 + 20
90 day
TCal ±1 °C
Range
95 % Confidence Level
99 % Confidence Level
365 day
TCal ±1 °C
±(ppm Reading + ppm Range) [4]
Absolute Uncertainties
RearFront
365 day
TCal ±5 °C

Fluke Corporation 8508A Extended Specifications 7
AC Voltage specifications
AC Voltage [1] [2] [6] [7]
Full Scale Uncertainty Relative to Cal Stds
24 hour
TCal ±1 °C
365 day
TCal ±1 °C
Absolute Uncertainties [9]
200 mV 199.999 9 1 - 10 80 + 70 120 + 70 120 + 70 160 + 70 165 + 70
10 - 40 80 + 20 120 + 20 120 + 20 130 + 20 140 + 20
40 - 100 60 + 20 100 + 20 100 + 20 110 + 20 115 + 20
100 - 2k 40 + 10 100 + 10 100 + 10 105 + 10 110 + 10
2k - 10k 60 + 20 100 + 20 100 + 20 105 + 20 135 + 20
10k - 30k 250 + 30 300 + 40 300 + 40 305 + 40 340 + 40
30k - 100k 400 + 100 700 + 100 700 + 100 705 + 100 765 + 100
2 V, 1.999 999 1 - 10 70 + 60 100 + 60 100 + 60 140 + 60 150 + 60
20 V & 19.999 99 10 - 40 70 + 10 100 + 10 100 + 10 105 + 10 115 + 10
200 V 199.999 9 40 - 100 50 + 10 80 + 10 80 + 10 85 + 10 90 + 10
100 - 2k 30 + 10 60 + 10 60 + 10 65 + 10 75 + 10
2k - 10k 50 + 10 80 + 10 80 + 10 85 + 10 110 + 10
10k - 30k 100 + 20 200 + 20 200 + 20 205 + 20 220 + 20
30k - 100k 250 + 100 500 +100 500 +100 505 + 100 570 + 100
100k - 300k 0.15% + 0.1% 0.3% + 0.1% 0.3% + 0.1% 0.3% + 0.1% 0.3% + 0.1%
300k - 1M 1% + 0.5% 1% + 1% 1% + 1% 1% + 1% 1% + 1%
1000 V [8] 1050.000 1 - 10 70 + 70 100 + 70 100 + 70 140 + 70 150 + 70
10 - 40 70 + 20 100 + 20 100 + 20 110 + 20 120 + 20
40 - 10k 50 + 20 80 + 20 80 + 20 95 + 20 115 + 20
10k - 30k 100 + 40 200 + 40 200 + 40 205 + 40 225 + 40
30k - 100k 250 + 200 500 + 200 500 + 200 510 + 200 580 + 200
200 mV 199.999 9 1 - 10 90 + 80 140 + 80 140 + 80 200 + 80 210 + 80
10 - 40 90 + 25 140 + 25 140 + 25 145 + 25 160 + 25
40 - 100 70 + 25 115 + 25 115 + 25 125 + 25 135 + 25
100 - 2k 45 + 12 115 + 12 115 + 12 125 + 12 135 + 12
2k - 10k 70 + 25 115 + 25 115 + 25 125 + 25 165 + 25
10k - 30k 270 + 35 340 + 50 340 + 50 345 + 50 395 + 50
30k - 100k 450 + 120 750 + 120 750 + 120 755 + 120 855 + 120
2 V, 1.999 999 1 - 10 80 + 70 115 + 70 115 + 70 180 + 70 190 + 70
20 V & 19.999 99 10 - 40 80 + 12 115 + 12 115 + 12 120 + 12 135 + 12
200 V 199.999 9 40 - 100 60 + 12 90 + 12 90 + 12 95 + 12 110 + 12
100 - 2k 35 + 12 70 + 12 70 + 12 75 + 12 90 + 12
2k - 10k 60 + 12 90 + 12 90 + 12 95 + 12 135 + 12
10k - 30k 115 + 25 240 + 25 240 + 25 245 + 25 260 + 25
30k - 100k 270 + 120 550 + 120 550 +120 555 + 120 650 + 120
100k - 300k 0.15% + 0.12% 0.3% + 0.12% 0.3% + 0.12% 0.3% + 0.12% 0.3% + 0.12%
300k - 1M 1% + 0.6% 1% + 1.2% 1% + 1.2% 1% + 1.2% 1% + 1.2%
1000 V [8] 1050.000 1 - 10 80 + 80 115 + 80 115 + 80 180 + 80 190 + 80
10 - 40 80 + 25 115 + 25 115 + 25 135 + 25 145 + 25
40 - 10k 60 + 25 90 + 25 90 + 25 110 + 25 140 + 25
10k - 30k 115 + 50 240 + 50 240 + 50 250 + 50 265 + 50
30k - 100k 270 + 250 600 + 250 600 + 250 615 + 250 700 + 250
90 day
TCal ±1 °C
Range
95 % Confidence Level
99 % Confidence Level
Frequency (Hz)
365 day
TCal ±1 °C
365 day
TCal ±5 °C
±(ppm Reading + ppm Range) [4]

8Fluke Corporation 8508A Extended Specifications
AC Voltage specifications (cont.)
Type True RMS, AC coupled measures AC component with up to 1000 V DC bias
on any range. DC coupled gives √(ac2+ dc2)
CMRR (1 kΩunbalance) [5] >90 dB DC - 60 Hz
Crest Factor
200 mV to 200 V ranges 10:1 at 12 % of range, 5:1 at 50 % of range, 2.5:1 at full range
1000 V range 10:1 at 25 % of range, 5:1 at full range
Protection (All ranges) 1 kV rms
Input Impedance 1 MΩ in parallel with 150 pF
DC Accuracy (DC Coupled) [13] Add ±(50 ppm Reading + 50 ppm Range + 20 µV)
Ratio Accuracy
Range to Range ±(Net Front Input Accuracy + Net Rear Input Accuracy)
Within Range Apply 24 hour or 20 minute Transfer Uncertainty specifications
Settling Time (to 100 ppm step size)
100 Hz <0.5 s
40 Hz <1.25 s
10 Hz <5 s
1 Hz <50 s
Frequency Measurement
Signal Amplitude Range 5 % of range to limit set by maximum V.Hz
Gate Mode Normal Fast
Resolution 6.5 digits 4.5 digits
Frequency Range 10 Hz - 1 MHz 200 Hz - 1 MHz
Accuracy (1 year, 13 °C - 33 °C) ± (10 ppm of Reading + 2 digits) ± 2 digits
Sample Interval 1 s 50 ms
AC Voltage (Secondary Specifications) [1] [2]
Temperature Coefficient
200 mV 1 - 10 510
10 - 40 510
40 - 100 510
100 - 2k 510
2k - 10k 12 20
10k - 30k 15 20
30k - 100k 40 60
2 V 1 - 10 510
20 V 10 - 40 510
200 V 40 - 100 510
100 - 2k 510
2k - 10k 10 15
10k - 30k 12 20
30k - 100k 40 60
100k - 300k 60 90
300k - 1M 80 120
1000 V 1 - 10 510
10 - 40 510
40 - 10k 10 15
10k - 30k 12 20
30k - 100k 40 60
Range
± ppm Reading/°C
15 °C - 30 °C
5 °C - 15 °C
30 °C - 40 °C
Frequency
(Hz)

Fluke Corporation 8508A Extended Specifications 9
AC Current specifications
AC Current [1] [2] [6] [9]
Full Scale Uncertainty Relative to Cal Stds
24 hour
TCal ±1 °C
365 day
TCal ±1 °C
Absolute Uncertainties [9]
200 µA, 199.999 9 1 - 10 200 + 100 250 + 100 250 + 100 290 + 100 310 + 100
2 mA & 1.999 999 10 - 10k 200 + 100 250 + 100 250 + 100 280 + 100 300 + 100
20 mA 19.999 99 10k - 30k 500+ 100 600 + 100 600 + 100 650 + 100 710 + 100
30k - 100k 0.35 % + 100 0.4 % + 100 0.4 % + 100 0.4 % + 100 0.4 % + 100
200 mA 199.999 9 1 - 10 200 + 100 250 + 100 250 + 100 290 + 100 310 + 100
10 - 10k 200 + 100 250 + 100 250 + 100 250 + 100 290 + 100
10k - 30k 500 + 100 600 + 100 600 + 100 600 + 100 625 + 100
2 A 1.999 999 10 - 2k 500 + 100 600 + 100 600 + 100 600 + 100 620 + 100
2k - 10k 600 + 100 700 + 100 700 + 100 700 + 100 725 + 100
10k - 30k 0.25 % + 100 0.3 % + 100 0.3 % + 100 0.3 % + 100 0.3 % + 100
20 A 19.999 99 10 - 2k 700 + 100 800 + 100 800 + 100 800 + 100 820 + 100
2k - 10k 0.2 % + 100 0.25 % + 100 0.25 % + 100 0.25 % + 100 0.25 % + 100
200 µA, 199.999 9 1 - 10 250 + 120 300 + 120 300 + 120 380 + 120 400 + 120
2 mA & 1.999 999 10 - 10k 250 + 120 300 + 120 300 + 120 340 + 120 370 + 120
20 mA 19.999 99 10k - 30k 600+ 120 700 + 120 700 + 120 775 + 120 800 + 120
30k - 100k 0.35 % + 120 0.4 % + 120 0.4 % + 120 0.4 % + 120 0.4 % + 120
200 mA 199.999 9 1 - 10 250 + 120 300 + 120 300 + 120 380 + 120 400 + 120
10 - 10k 250 + 120 300 + 120 300 + 120 305 + 120 360 + 120
10k - 30k 600 + 120 700 + 120 700 + 120 700 + 120 740 + 120
2 A 1.999 999 10 - 2k 600 + 120 700 + 120 700 + 120 705 + 120 725 + 120
2k - 10k 700 + 120 800 + 120 800 + 120 815 + 120 860 + 120
10k - 30k 0.25 % + 120 0.3 % + 120 0.3 % + 120 0.3 % + 120 0.3 % + 120
20 A 19.999 99 10 - 2k 800 + 120 900 + 120 900 + 120 900 + 120 920 + 120
2k - 10k 0.2 % + 120 0.25 % + 120 0.25 % + 120 0.25 % + 120 0.25 % + 120
90 day
TCal ±1 °C
Range
95 % Confidence Level
99 % Confidence Level
Frequency
(Hz)
365 day
TCal ±1 °C
365 day
TCal ±5 °C
±(ppm Reading + ppm Range) [4]

10 Fluke Corporation 8508A Extended Specifications
Type True RMS, AC coupled. DC coupled gives √(ac2+ dc2)
Crest Factor 3:1 at 50 % of range, 1.5:1 at full range
Protection
Front Input 20 A rms
Rear Input 2 A rms, Rear Panel Fuse
Settling Time (to 100 ppm step size) 200 µΑ to 2 A Ranges 20 A Range
100 Hz <0.5 s <30 s
40 Hz <1.25 s <30 s
10 Hz <5 s <30 s
1 Hz <50 s <50 s
AC Current (Secondary Specifications) [1] [2] [6] [9]
Temperature Coefficient
200 µA, 1 - 10 10 15 200 µA150 150
2 mA & 10 - 10k 10 15 2 mA 15.2 15.2
20 mA 10k - 30k 12 20 20 mA 1.8 1.9
30k - 100k 40 60
200 mA 1 - 10 10 15 1.2 1.3
10 - 10k 15 20
10k - 30k 15 20
2 A 10 - 2k 10 15 0.3 0.4
2k - 10k 15 20
10k - 30k 20 30
20 A 10 - 2k 10 15 0.04 -
2k - 10k 15 20
Range
± ppm Reading/°C
15 °C - 30 °C
5 °C - 15 °C
30 °C - 40 °C
Frequency
(Hz)
AC Current specifications (cont.)
RearFront
Range
Input
Impedance
(Ω)

Fluke Corporation 8508A Extended Specifications 11
Resistance specifications
Resistance [1] [2] [3] [9]
Full Scale Uncertainty Relative to Cal Stds
24 hour
TCal ±1 °C
365 day
TCal ±1 °C
Absolute Uncertainties
2 Ω1.999 999 99 Normal 5.0 + 2.0 8.0 + 2.0 10 + 2.0 15 + 2.0 17 + 2.0
20 Ω19.999 999 9 Normal 2.5 + 0.7 4.5 + 0.7 7.0 + 0.7 9.0 + 0.7 9.5 + 0.7
200 Ω199.999 999 Normal 1.5 + 0.25 4.0 + 0.25 7.0 + 0.25 7.5 + 0.25 8.0 + 0.25
2 kΩ1.999 999 99 Normal 1.0 + 0.25 3.5 + 0.25 7.0 + 0.25 7.5 + 0.25 8.0 + 0.25
20 kΩ19.999 999 9 Normal 1.0 + 0.25 3.5 + 0.25 7.0 + 0.25 7.5 + 0.25 8.0 + 0.25
200 kΩ199.999 999 Normal 1.0 + 0.25 3.5 + 0.25 7.0 + 0.25 7.5 + 0.25 8.0 + 0.25
2 MΩ1.999 999 99 Normal 2.0 + 0.5 4.0 + 0.5 7.0 + 0.5 8.5 + 0.5 9.0 + 0.5
20 MΩ19.999 999 9 Normal 3.5 + 5.0 6.0 + 5.0 9.0 + 5.0 15 + 5.0 20 + 5.0
200 MΩ199.999 999 Normal 20 + 50 25 + 50 30 + 50 60 + 50 120 + 50
2 GΩ1.999 999 99 Normal 250 + 500 350 + 500 500 + 500 525 + 500 1510 + 500
2 Ω1.999 999 99 Lo Current 5.0 + 2.0 8.0 + 2.0 10 + 2.0 15 + 2.0 17 + 2.0
20 Ω19.999 999 9 Lo Current 2.5 + 0.7 4.5 + 0.7 7.0 + 0.7 9.0 + 0.7 9.5 + 0.7
200 Ω199.999 999 Lo Current 2.5 + 0.7 5.0 + 0.7 7.0 + 0.7 7.5 + 0.7 8.0 + 0.7
2 kΩ1.999 999 99 Lo Current 2.5 + 0.7 5.0 + 0.7 7.0 + 0.7 7.5 + 0.7 8.0 + 0.7
20 kΩ19.999 999 9 Lo Current 2.5 + 0.7 5.0 + 0.7 7.0 + 0.7 7.5 + 0.7 8.0 + 0.7
200 kΩ199.999 999 Lo Current 5.0 + 0.5 6.5 + 0.5 7.0 + 0.5 7.5 + 0.5 8.0 + 0.5
2 MΩ1.999 999 99 Lo Current 7.0 + 0.5 8.0 + 0.5 9.0 + 0.5 10 + 0.5 15 + 0.5
20 MΩ19.999 999 9 Lo Current 20 + 5.0 20 + 5.0 25 + 5.0 35 + 5.0 90 + 5.0
200 MΩ199.999 999 Lo Current 250 + 500 350 + 500 500 + 500 515 + 500 1505 + 500
2 GΩ1.999 999 99 Lo Current 250 + 500 350 + 500 500 + 500 525 + 500 1510 + 500
20 MΩ19.999 999 9 High Voltage 2.0 + 0.5 4.0 + 0.5 7.0 + 0.5 15 + 0.5 17 + 0.5
200 MΩ199.999 999 High Voltage 3.5 + 5.0 6.0 + 5.0 9.0 + 5.0 60 + 5.0 65 + 5.0
2 GΩ1.999 999 99 High Voltage 20 + 50 25 + 50 30 + 50 150 + 50 180 + 50
20 GΩ19.999 999 9 High Voltage 250 + 500 350 + 500 500 + 500 525 + 500 1510 + 500
2 Ω1.999 999 99 Normal 6.0 + 2.5 10 + 2.5 12 + 2.5 19 + 2.5 22 + 2.5
20 Ω19.999 999 9 Normal 3.0 + 0.9 5.5 + 0.9 8.5 + 0.9 11.5 + 0.9 12.0 + 0.9
200 Ω199.999 999 Normal 1.8 + 0.3 5.0 + 0.3 8.5 + 0.3 9.5 + 0.3 10 + 0.3
2 kΩ1.999 999 99 Normal 1.2 + 0.3 4.5 + 0.3 8.5 + 0.3 9.5 + 0.3 10 + 0.3
20 kΩ19.999 999 9 Normal 1.2 + 0.3 4.5 + 0.3 8.5 + 0.3 9.5 + 0.3 10 + 0.3
200 kΩ199.999 999 Normal 1.2 + 0.3 4.5 + 0.3 8.5 + 0.3 9.5 + 0.3 10 + 0.3
2 MΩ1.999 999 99 Normal 2.5 + 0.6 5.0 + 0.6 8.5 + 0.6 10.5 + 0.6 12 + 0.6
20 MΩ19.999 999 9 Normal 4.5 + 6.0 7.5 + 6.0 12 + 6.0 20 + 6.0 25 + 6.0
200 MΩ199.999 999 Normal 25 + 60 30 + 60 35 + 60 75 + 60 150 + 60
2 GΩ1.999 999 99 Normal 325 + 600 450 + 600 650 + 600 675 + 600 1810 + 600
2 Ω1.999 999 99 Lo Current 6.0 + 2.5 10 + 2.5 12 + 2.5 19 + 2.5 22 + 2.5
20 Ω19.999 999 9 Lo Current 3.0 + 0.9 5.5 + 0.9 8.5 + 0.9 11.5 + 0.9 12.0 + 0.9
200 Ω199.999 999 Lo Current 3.0 + 0.9 6.5 + 0.9 8.5 + 0.9 9.5 + 0.9 10.0 + 0.9
2 kΩ1.999 999 99 Lo Current 3.0 + 0.9 6.5 + 0.9 8.5 + 0.9 9.5 + 0.9 10.0 + 0.9
20 kΩ19.999 999 9 Lo Current 3.0 + 0.9 6.5 + 0.9 8.5 + 0.9 9.5 + 0.9 10.0 + 0.9
200 kΩ199.999 999 Lo Current 6.0 + 0.6 8.0 + 0.6 9.0 + 0.6 9.5 + 0.6 10.0 + 0.6
2 MΩ1.999 999 99 Lo Current 8.0 + 0.6 10.0 + 0.6 12.0 + 0.6 13.0 + 0.6 17.0 + 0.6
20 MΩ19.999 999 9 Lo Current 25 + 6.0 25 + 6.0 30 + 6.0 45 + 6.0 110 + 6.0
200 MΩ199.999 999 Lo Current 325 + 600 450 + 600 650 + 600 670 + 600 1810 + 600
2 GΩ1.999 999 99 Lo Current 325 + 600 450 + 600 650 + 600 675 + 600 1810 + 600
20 MΩ19.999 999 9 High Voltage 2.5 + 0.6 5.0 + 0.6 8.5 + 0.6 19 + 0.6 20 + 0.6
200 MΩ199.999 999 High Voltage 4.5 + 6.0 7.5 + 6.0 12 + 6.0 75 + 6.0 80 + 6.0
2 GΩ1.999 999 99 High Voltage 25 + 60 30 + 60 35 + 60 195 + 60 230 + 60
20 GΩ19.999 999 9 High Voltage 325 + 600 450 + 600 650 + 600 675 + 600 1810 + 600
90 day
TCal ±1 °C
Range
95 % Confidence Level
99 % Confidence Level
Mode [10]
365 day
TCal ±1 °C
365 day
TCal ±5 °C
±(ppm Reading + ppm Range) [4]

12 Fluke Corporation 8508A Extended Specifications
Type True 4-wire with Ohms guard. 2-wire selectable.
Max Lead Resistance 10 Ωin any or all leads, 1 Ω on 2 Ωrange
Full Scale Measurement Voltage
Normal Mode 200 mV/2 V/20 V
Lo Current Mode 200 mV/2 V
High Voltage Mode 200 V
Protection (All ranges) 250 V rms, 360 V pk
Ratio Accuracy
Range to Range ±(Net Front Input Accuracy + Net Rear Input Accuracy)
Within Range Apply 24 hour or 20 minute Transfer Uncertainty specifications
Settling Time Up to 200 kΩrange generally the same as DC Voltage Filter In but
depends on external connections
Resistance - Normal Mode (Secondary Specifications) [1] [2] [3] [10]
Transfer
Uncertainty
20 mins ±1 °C
± (ppm Reading
+ ppm Range)
Temperature Coefficient
2 Ω100 mA 2.0 + 2.0 1.5 2.5
20 Ω10 mA 0.8 + 0.7 0.6 1.0
200 Ω10 mA 0.2 + 0.15 0.5 0.8
2 kΩ1 mA 0.2 + 0.15 0.5 0.8
20 kΩ100 µA0.2 + 0.15 0.5 0.8
200 kΩ100 µA0.2 + 0.15 0.5 0.8
2 MΩ10 µA0.5 + 0.5 0.6 1.0
20 MΩ1 µA2.5 + 5 2 3
200 MΩ100 nA 15 + 50 20 30
2 GΩ10 nA 200 + 500 200 300
± ppm Reading/°C
15 °C - 30 °C
5 °C - 15 °C
30 °C - 40 °C
Measurement
Current
Resistance specifications (cont.)
Resistance - Lo Current Mode (Secondary Specifications) [1] [2] [3] [10]
Temperature Coefficient
2 Ω100 mA 2.0 + 2.0 1.5 2.5
20 Ω10 mA 0.8 + 0.7 0.6 1.0
200 Ω1 mA 0.8 + 0.7 0.6 1.0
2 kΩ100 µA0.8 + 0.7 0.6 1.0
20 kΩ10 µA0.8 + 0.7 0.6 1.0
200 kΩ10 µA0.5 + 0.5 0.6 1.0
2 MΩ1µA2.0 + 0.5 2 3
20 MΩ100 nA 15 + 5 20 30
200 MΩ10 nA 200 + 500 200 300
2 GΩ10 nA 200 + 500 200 300
± ppm Reading/°C
15 °C - 30 °C
5 °C - 15 °C
30 °C - 40 °C
Measurement
Current
Resistance - High Voltage Mode (Secondary Specifications) [1] [2] [3]
Temperature Coefficient
20 MΩ10 µA0.5 + 0.5 0.6 1.0
200 MΩ1 µA2.0 + 0.5 2.0 3
2 GΩ100 nA 15 + 50 20 30
20 GΩ10 nA 200 + 500 200 300
± ppm Reading/°C
15 °C - 30 °C
5 °C - 15 °C
30 °C - 40 °C
Measurement
Current
Transfer
Uncertainty
20 mins ±1 °C
± (ppm Reading
+ ppm Range)
Transfer
Uncertainty
20 mins ±1 °C
± (ppm Reading
+ ppm Range)
Range
Range
Range [9]

Fluke Corporation 8508A Extended Specifications 13
Temperature specifications
Type 4-wire current reversal resistance measurement with readout of equivalent temperature.
2-wire and 3-wire selectable without current reversal. Refer to Resistance specifications for
additional details.
Temperature Range -200 °C to 660 °C, readout also available in °F or K.
Linearization ITS-90 or Callendar van Dusen. Entry and storage of coefficients and nominal resistance for
up to 100 probes.
Current Source 1 mA
Temperature Readout (Secondary Specifications) [1] [2] [3]
Resistance Measurement Uncertainty
0 - 199.999 999 Ω0.8 + 0.14 0.1 0.005 0.6 1.0
200 - 1999.999 99 Ω0.2 + 0.5 0.1 0.005 0.5 0.8
2-Wire Adder
(Ω)
Transfer Uncertainty
20 Minute ±1 °C
±(ppm Reading + mΩ)[11]
Resistance
Range Temp Coeff. ± ppm Reading/°C
3-Wire Adder
(Ω)15 °C - 30 °C
5 °C - 15 °C
30 °C - 40 °C
Temperature Readout [1] [2] [3]
Typical Equivalent Temperature Measurement Uncertainty [12]
0 - 199.999 999 Ω7.5 + 0.14 25 ΩPRT/SPRT -200 50.0085
25 ΩPRT/SPRT 025 0.0035
25 ΩPRT/SPRT 660 84 0.0025
100 Ω PRT/SPRT -200 20 0.0035
100 Ω PRT/SPRT 0100 0.0025
100 Ω PRT/SPRT 232 185 0.0020
200 - 1999.999 99 Ω7.5 + 0.5 100 Ω PRT/SPRT 400 250 0.0025
0 - 199.999 999 Ω9.5 + 0.18 25 ΩPRT/SPRT -200 50.0100
25 ΩPRT/SPRT 025 0.0040
25 ΩPRT/SPRT 660 84 0.0025
100 Ω PRT/SPRT -200 20 0.0040
100 Ω PRT/SPRT 0100 0.0025
100 Ω PRT/SPRT 232 185 0.0020
200 - 1999.999 99 Ω9.5 + 0.6 100 Ω PRT/SPRT 400 250 0.0025
Probe
Type
Absolute Resistance
Measurement Uncertainty
365 day TCal ±1 °C [4]
±(ppm Reading + mΩ) [11]
Resistance
Range
Nominal
Temp (°C)
Resistance
(Ω)
Accuracy
± (°C)
95 % Confidence Level
99 % Confidence Level

14 Fluke Corporation 8508A Extended Specifications
Read Rate and additional Uncertainty
Read Rate and Additional Uncertainty Specifications
ResolutionFunction
DCV, DCI &
Ohms [10]
ACV & ACI [6]
Normal Fast Normal Fast
Filter
Frequency
(Hz)
Read Rate
(readings/second) Additional Errors [13]
±(ppm Reading +
ppm Range)
81/25 1/6 0 + 0 0 + 0.1
71/6 1/2 0 + 0.1 0 + 0.5
6 2 35 1.0 + 0.5 0 + 2.5
5 35 150 0 + 5 0 + 25
6 1 1/50 0 + 0
10 1/5 0 + 0
40 1/2 0 + 0
100 1 0 + 0
5 1 1/50 0 + 5
10 1/5 0 + 5
40 1/2 0 + 5
100 2 0 + 5
11/25 200 + 20
10 1/2.5 200 + 20
40 1 200 + 20
100 4 200 + 20
8-1/90 1/30 0 + 0
7-1/30 1/10 0 + 0.1
6-1/4 1/3 1.0 + 0.5
5-1/3 1/3 0 + 5
PRT & Tru
Ohms [14]
ACV Transfer
Off [6]

Fluke Corporation 8508A Extended Specifications 15
Notes:
[1] Specifications apply for max resolution in each function, normal mode
[2] Assumes 4 hour warm-up period
[3] Input zero or offset null required whenever the temperature moves more than ±1 °C from the temperature at which the
previous null/zero was performed
[4] TCal = Ambient calibration temperature
[5] Integration time > 1 Power Line cycle
[6] Valid for signals >1 % Full Scale, Transfer Mode On. Signal must be DC coupled <40 Hz. Readings invalid with Transfer Mode
On and 1 Hz filter selected when using internal trigger mode
[7] Max Volt.Hertz 3 x 107
[8] >300 V, <10 kHz add: ±0.0004 (R-300)2ppm
>300 V, 10 kHz - 30 kHz add: ± (0.0004 + (F - 10000)*1E-7)*(R-300)2 ppm
>300 V, >30 kHz add: ±0.0024 (R-300)2ppm
[9] Typical below 10 Hz for ACV, below 10 Hz, and above 10 kHz for ACI and above 2 GΩfor Resistance
[10] Tru Ohms mode available on 2 Ωto 20 kΩranges. Read Rate reduced in Tru Ohms mode. Specification for Tru Ohms same as
corresponding Normal or Lo Current range.
[11] Valid for 4-wire sensor
[12] Not including sensor uncertainty
[13] Assume Range and Full Scale = 2000 V when calculating for 1000 V Range. For DCI, additional errors only apply in 5 digit
resolution
[14] Fast mode not available in PRT
General specifications
General Specifications
Power
Voltage 100 V to 120 V ±10 %
or 200 V to 240 V ±10 %
Frequency 47 Hz to 63 Hz
Consumption 80 VA
Dimensions
Height 88 mm (3.5 inches)
Width 427 mm (16.8 inches)
Depth 487 mm (19.2 inches)
Weight 11.5 kg (25.5 lbs)
Environment
Temperature:
Operating 0 °C to 50 °C
Specified Operation 5 °C to 40 °C
Calibration (TCal) 20 °C to 25 °C
Factory Cal Temperature 23 °C
Storage -20 °C to 70 °C
Warm Up 4 hours to full uncertainty
specification
Relative Humidity: (non condensing)
Operating < 90 % (5 °C to 40 °C)
Storage < 95 % (0 °C to 70 °C)
Altitude:
Operating < 2000 m
Storage < 12000 m
Vibration and Shock: Complies with MIL-PRF-28800F Class 3
EMC EN50081-1 Class B, EN55011/22,
EN61326-1:1998, EN50082-1,
EN55011 1991 Class B,
EN61000-6-1:2001, FCC Rules part 15
sub part J class B, CE marked.
General Specifications (cont.)
Safety Designed and tested to EN61010-1-2001,
UL 61010-1A1,
CAN/CSA 22.2 No. 61010.1,
CE and ETL marked.
Pollution Degree 2.
Installation Category II.
Equipment Class I (single insulation /
Earthed metal case).
Protection against water ingress IP4X
(general indoor conditions).
Input circuitry and connections
(creepage and clearances) designed to
interface at Installation or Measurment
Category I.
Measurement Isolation
Guard to Safety Ground <3300 pF, >10 GΩ
Lo to Guard:
In Remote Guard <2800 pF, >10 GΩ
(Not in Resistance function)
In Local Guard Lo and Guard terminals are internally shorted
(in Resistance <2800 pF, >10 GΩ)
Autorange
Range Up 100 % of nominal range
Range Down 9 % of nominal range (18 % on 1 kV range)
Remote Interface IEEE 488.2
Warranty 1 Year

Model
8508A 8.5 digit Reference Multimeter, Certificate of Calibration and User Manual
8508A/01 8.5 digit Reference Multimeter with front & rear input binding posts,
Certificate of Calibration and User Manual
Accessories
NVLAP NVLAP Accredited Calibration
UKAS UKAS Accredited Calibration
8508A-SPRT Standard Platinum Resistance Thermometer
8508A-PRT 100 ΩPRT
8508A-LEAD Comprehensive Measurement Lead Kit
Y8508 Rack Mount Kit
Y8508S Rack Mount Kit Slides
8508-7000K Calibration Kit
Fluke Corporation 8508A Extended Specifications
Fluke Corporation
PO Box 9090, Everett, WA USA 98206
Fluke Europe B.V.
PO Box 1186, 5602 BD
Eindhoven, The Netherlands
For more information call:
In the U.S.A. [phone] or
Fax [phone]
In Europe/M-East/Africa (31 40) 2 675 200 or
Fax [phone]
In Canada (800)-36-FLUKE or
Fax [phone]
From other countries [phone] or
Fax [phone]
Web access: http://www.fluke.com/
©2002 Fluke Corporation. All rights reserved.
Trademarks are the property of their respective
owners.
Printed in UK 10/2002 1887212 D-ENG-N Rev C,
DS263
Fluke. Keeping your world
up and running.
Ordering information
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