OM 21 (1) - AOIP, Instrumentation de test et mesure, contrôle moteur
OM 21 (2) - AOIP, Instrumentation de test et mesure, contrôle moteur
OM 21 (3) - AOIP, Instrumentation de test et mesure, contrôle moteur
OM 21 (4) - AOIP, Instrumentation de test et mesure, contrôle moteur

OM 21

picto fleche Programmable benchtop micro-ohmmeter – High accuracy: 0.03 %

OM 21 benchtop micro-ohmmeter is used for 4-wire measurement of very low resistance values up to 20 kΩ with an accuracy of 0.03% RDG and a 0.1 µΩ resolution. The reliability and accuracy of the measurements is improved by a low temperature coefficient of 10 ppm/°C, automatic removal of EMF parasites before each measurement, metal temperature compensation and compensation of ambient temperature.

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OM 21 benchtop micro-ohmmeter is used for 4-wire measurement of very low resistance values up to 20 kΩ with an accuracy of 0.03% RDG and a 0.1 µΩ resolution. The reliability and accuracy of the measurements is improved by a low temperature coefficient of 10 ppm/°C, automatic removal of EMF parasites before each measurement, metal temperature compensation and compensation of ambient temperature.

With three current waveforms available -continuous, pulse or AC current- from 100 µA to 10 A and high flexibility of trigger and sampling conditions, OM 21 low resistance ohmmeter covers a wide range of applications: Cable resistance and resistivity measurement, inductive resistance measurement (motors and transformers winding resistance), contact resistance measurement (connectors, switches, relays…), test of low power electrical components (fuses…) and heat sensitive devices, metallisation / earth bonding and ground continuity measurement.

OM 21 is fully programmed by the user, either directly through the instrument interface or through LOG OM data management software delivered in option: choice of measuring current, resistance range, measuring unit, metal under test, alarms, triggering conditions, storage of measurement…

Up to 1,000 samples can be stored inside the instrument and be recalled directly on the display or on computer via LOG OM.

Powered from mains or from rechargeable batteries, the electronic calibration of the instrument is performed without any internal adjustment.

For use on test benches, you might want to consider OM 22 micro-ohmmeter instead of OM 21. It has the exact same specifications of OM 21 but is more adapted to repetitive measurement tasks. While OM 21 can be either manually or automatically operated and is fully programmable by the user through the instrument interface, OM 22 has 6 set configurations inside to be selected by the user. More information over OM 22 here.

Resistance measurement

Range Resolution Accuracy at 90 days
(23°C ±1°C)		 Measuring current Voltage drop
2 mΩ 0.1 μΩ 0.05% + 0.3 μΩ 10 A 20 mV
20 mΩ 1 μΩ 0.05% + 2 μΩ 10 A 200 mV
20 mΩ 1 μΩ 0.05% + 3 μΩ 1 A 20 mV
200 mΩ 10 μΩ 0.05% + 10 μΩ 10 A 2 V
200 mΩ 10 μΩ 0.05% + 20 μΩ 1 A 200 mV
200 mΩ 10 μΩ 0.05% + 30 μΩ 100 mA 20 mV
2 Ω 100 μΩ 0.05% + 100 μΩ 1 A 2 V
2 Ω 100 μΩ 0.03% + 200 μΩ 100 mA 200 mV
2 Ω 100 μΩ 0.03% + 300 μΩ 10 mA 20 mV
20 Ω 1 mΩ 0.03% + 1 mΩ 100 mA 2 V
20 Ω 1 mΩ 0.03% + 2 mΩ 10 mA 200 mV
20 Ω 1 mΩ 0.03% + 3 mΩ 1 mA 20 mV
200 Ω 10 mΩ 0.03% + 10 mΩ 10 mA 2 V
200 Ω 10 mΩ 0.03% + 20 mΩ 1 mA 200 mV
200 Ω 10 mΩ 0.03% + 30 mΩ 100 µA 20 mV
2 kΩ 100 mΩ 0.03% + 100 mΩ 1 mA 2 V
2 kΩ 100 mΩ 0.03% + 200 mΩ 100 µA 200 mV
20 kΩ 1 Ω 0.03% + 1 Ω 100 µA 2 V

Automatic or manual selection of measurement range
Accuracy given in % of reading + counts over 90 days at 23 ±1°C
Maximum capacity: 26,000 counts

Max. open circuit voltage: 3 V (can be limited to 20 mV or 50 mV at the terminals of the resistor to be measured)

Further features

Resistance types
  • Inductive resistances: Coils, transformers, motor windings...
  • Non-inductive resistances: Earth bonding, coating, contact resistances...
Measuring current
  • Internal or external source
  • DC current from 100 µA to 10 A
  • Continuous, pulsed or pulsed alternated
Measurement time < 1 s in direct current mode
< 1,5 s in pulse current mode
< 2 s in alternate current mode
Measurement trigger conditions Manual or automatic trigger from 2 measures/s to 1 measure/9h, allowing a single operator to be able to perform measurements
EMFs Automatic compensation of EMF parasites before each measurement for a greater accuracy
Temperature compensation Choice of metal temperature coefficient
Choice of ambient temperature (programmed or measured with external probe)
Temperature compensation at 20°C: Resolution: 0.1°C, accuracy: ±0.5°C
(R20 = Resistance compensated at ambient temperature equal to 20°C
Temperature coefficient beyond operating range < 10% accuracy/°C
Relative measurements Display L = R-R0 or L = 100 x (R-R0)/R0 in %
Where L: read value, R: measured value and R: reference value either recalled from memory or entered by the operator
Coil heating calculation Coil heating calculation according to ambient temperature, original coil resistance at ambient temperature, coil resistance once heated and coil material
Alarms 2 programmable thresholds with visual and sound signal and relay outputs
Outputs
  • Two relays (1 A / 220 VAC)
  • 1 analogue output 0 – 2.5 V (load >= 2.5 kΩ, resolution: 10 mV, accuracy: ±10 mV)
Calibration Digital calibration without internal adjustment

General specifications

Size 225 x 88 x 310 mm
Weight 2 to 3 kg depending on options
Display LCD 26,000 counts, 16 figures lighted, 11.5 mm high
Power supply 115 / 230 V (50 / 60 Hz)
Battery with internal charger(option) Type: 12 V battery pack
Battery life:2 to 8 h according to use
Charging time: 14 h
Communication ports
  • RS 232 in standard
  • IEEE 488-2 in option

Allows programming, data management and unit calibration directly from a computer
Storage capacity 1,000 measurements with average, minimum and maximum value
Memory reading directly on the display or through digital and analogue interfaces

Environmental specifications

Reference range 23°C ±1°C (RH: 45 to 75 % w/o condensing)
Operating reference range 0 to 50°C (RH: 20 to 80 % w/o condensing)
Limit operating range -10°C to +50°C (RH: 10 to 80 % w/o condensing)
Storage temperature limits -30°C to +55°C
(- 15°C to + 50°C for model with battery)
Protection IP IP40 according to EN60529
Maximum altitude 2,500 m

Safety specifications

Protections
  • Electronic protection for ‘voltage’ wires
  • Fuse protection for ‘current’ wires
  • Protection against ‘current’ circuit breaking during inductive resistance measurements
Class In accordance with EN 61010-1
Category III, pollution 2
Rated voltage 50 V
Chocks and vibrations EN61010-1
EMC conformity Immunity:

  • EN 50082-1/1992

Conducted and radiated emissions:

  • EN 55022, class B
  • Radiated: IEC 801-3/1984
  • Conducted: IEC 801-4/1988
  • Electrostatic discharges: IEC 801-2/1991

Instrument:

OM 21-1                 Programmable benchtop micro-ohmmeter

                            With RS 232 interface

OM 21-2                 Programmable benchtop micro-ohmmeter

                            With RS 232 interface and battery + charger

OM 21-3                 Programmable benchtop micro-ohmmeter

                            With RS 232 interface and IEEE 488

OM 21-4                 Programmable benchtop micro-ohmmeter

                            With RS 232 interface, IEEE 488 and battery + charger

Clips and probes:

Please note that 2 clips are needed per OM 21.

AN5806-2               Gold plated Kelvin clips, set of 2

                            Opening diameter: 12 mm, cable length: 2 m 

AN5806C               Kelvin clips, set of 2

                            Opening diameter: 12 mm, cable length: 3 m

AMT003                 Test probe, per unit

                            Cable length: 5 m

AMT004                 Kelvin clip, per unit

                            Opening diameter: 25 mm, cable length: 3 m

Other accessories:

LOG OM                Configuration & exploitation software for OM 21

                            Including RS 232 cable 

AN6901                 Soft case for benchtop instruments

AMT002                 External power supply 3 V – 10 A

AN5883                 Bracket mounting for panel installation (T2 box type)

AN5884                 Rack mounting kit for rack installation (T2 box type)

AN5875                 RS232 9p F cable

AN5836                 IEEE 488 cable

                            Length: 2 m

AN8009                 Set of 10 fuses – 16 A

 

Certification:

QMA11EN              COFRAC certificate of calibration

Product Description Release Type
Accessories

Brochure for clips, probes and further accessories

 07 / 2014 pdf
Aoom2x

Labview© driver

 A.08 zip
LOG OM

Data management software

 B.05 zip
OM 21

Instruction manual

 pdf