The leading DMM for metrologists
The 1281 provides supreme measurement capability and is an industry standard in terms of accuracy, traceability, and ease of use. In fact, it has the world's best measurement uncertainties.
Combining a method of internal calibration with innovative circuit design, the 1281 DMM produces performance across an entire range of functions. At the same time, it is affordable and uniquely addresses the needs of laboratory applications. Designed with standards and calibration laboratories in mind, the 1281 provides the ultimate in accurate functional capability.
The 1281's excellent stability, linearity and resolution, combined with its unique ratio and GPIB capabilities, makes it a practical alternative to Null detectors, Kelvin-Varley dividers and resistance bridges. Furthermore, the 1281 has additional Ohms measurement features including "Ohms guard," Low current mode and unique "True Ohms" to help reduce measurement errors associated with thermal emfs.
- 8½ digit scale length with usable last-digit resolution.
- 100% over-ranging maintains 10 GΩ input impedance up to 20 V.
- Stable enough to replace standard cells. Much easier to use.
Simultaneous readout of AC voltage/current and frequency saves the cost of an additional instrument in ATE systems.
Three separate input channels save the cost of an external scanner and allow function-to-function ratio measurements.
Special Ohms Functions: '2/4-Wire Ohms' eliminates errors due to lead resistance. 'True Ohms' eliminates errors due to thermal emfs. 'LoI Ohms' minimises self-heating in PRTs and allows in-circuit measurements with diode junctions in parallel. 'Ohms Guard' allows in-circuit resistance measurements and guards out leakage paths.
- Access secondary functions using no more than two front-panel keystrokes, followed if necessary by simple numeric entry.
- Comprehensive self-test ensures maximum operability.
- Trade speed for resolution to optimise performance in every application.
- Monitor functions give instant access to measurement uncertainties and secondary measurement parameters.
- Math functions allow direct display of derived values.
Working for cal lab efficiency
While continuously striving to reduce measurement uncertainties, calibration laboratories are also under commercial pressure to reduce costs. Calibration equipment needs to be chosen not only for the uncertainty levels it can deliver, but also the range of uses to which it can be put. For accuracy coupled with versatility, no other standards laboratory DMM matches the superb performance of the 1281.
At the heart of the 1281, two specially conditioned 10-volt zener references are continuously inter-compared to minimize drift rate. Coupled with the dc input amplifier's incredibly low 0.25 µV/°C temperature coefficient, this allows the 1281 to achieve a 10-volt range stability over a 1 year period and ±5°C temperature range of 3ppm. That's as good as many Weston cells. And because the 1281's temperature coefficient is far superior to a Weston cell's, you don't have to worry about precision temperature control. Add the fact that it offers exceptional 0.1 ppm (± 2 µV) single-range linearity from zero to 20V, and you realise that the 1281 not only substitutes for Weston cells. It also doubles up as a highly sensitive null detector (with an input impedance >10Ω) and a Kelvin Varley divider.
The 1281 also features exceptional AC performance, with 1-year uncertainties significantly below 100 ppm up to 10 kHz on its 1V to 100V ranges. Its 'spot calibrated frequency' feature gives you even greater precision. Coupled with unique AC/DC transfer capabilities, this allows the 1281 to replace a conventional thermal transfer standard.
The 1281 also has unique Ohms measurement features. Its active 'Ohms Guard' terminal lets you guard out leakage current paths when measuring very high value resistors. And its 'LoI' mode prevent excessive self-heating in PRTs. The 1281's 2-input ratio function allows you to use it as a high performance automated bridge. When you purchase the 1281 you're not only buying a multi-function DMM. You're also buying a multi-purpose instrument that's much easier to use than traditional cal lab equipment. Plus you'll benefit from more than 25 year's of experience in leading edge standards lab metrology.
The 1281 can replace:
- Standard 'Weston' Cells
- Null Detectors and µV Meters
- Kelvin Varley Dividers
- Thermal Transfer Standards
- Resistance Bridges
General Specifications Voltage DC Range 0 to ±1000V Best 1 Year Specification 3.1 ppm Voltage AC Range 100 mV to 1000V
40 Hz to 1 MHz
Best 1 Year Specification 60 ppm Current DC Range 0 to ± 2A Best 1 Year Specification 25 ppm Current AC Range 10 Hz to 5 kHz
100 mA to 2A
Best 1 Year Specification 200 ppm Resistance Range 10Ω to 1 GΩ Best 1 Year Specification 6 ppm
Model Name Description Fluke 1281 Fluke 1281 Precision Digital Multimeter
Precision Digital Multimeter
- Rear/Ratio input
- IEEE-488.2 interface
Model Name Description Fluke 1281-90 Fluke 1281-90 Rack Mount Kit
Title How to Diagnose PMW Peak Voltage Using a Multimeter and a Scope Download