Cầu đo điện trở một chiều Sonel MMR-630 (1.0μΩ ~1999,9 Ω)

• Measurement of resistive object type:
  - welded and soldered connections, equipotential bonding, earth wire,
  - terminals and connectors, rail welded joints, cables and wires,
  - measurement 4-pole method.
• Measurement of inductive object type:
  - coils (motors and transformers), low resistance coils.
• Range selection autoranging or manual (measurement of inductive object type).
• Selectable measurement mode adjusted to object type:
  - for resistive objects - fast mode (3 seconds),
  - for inductive objects - long mode with automatic discharge after measurements (or with lower accuracy - shorter mode).
• Selectable measurement mode adjusted to application:
  - normal mode - after pushing „START” button,
  - automatic mode - since test leads are connected to the object meters automatically starts measurement with dual direction current flow and gives average result - what eliminates eventual DC voltage on tested object,
  - continuous mode - every 3 seconds for resistive objects or continuous measurement for inductive objects.
• Window mode:
  - this option enables setting an upper and a lower limit between which the average measurement result is bound to appear. The results outside of this range will be indicated by two long audible signals and the symbols.
• MMR-630 is designated not to be effected by interference up to 20 mV and to show noises from 20 to 100 mV (so in edge conditions even 5 times higher than measured drop of potential).
• Memory store for up to 990 results and a communications facility for transferring data from the device to a PC.

Electric security:
- type of insulation: double, according to EN 61010 - 1 and IEC 61557
- measurement category: CAT III 300 V acc. to EN 61010 - 1
- protection class acc. to EN 60529: IP54

Other technical data:
- meter’s power supply: battery package SONEL/Ni-MH 4,8 V
- battery charging time: approx. 2,5 hours
- number of measurements with the current of 10 A: 300
- auto-off time: 120 seconds
- immunity to interference: additional error ≤1% for voltage 50 Hz ≤100 mV RMS
- maximum leads resistance for the 10 A current: 0,1 Ω
- maximum inductance of the tested object: 40H
- accuracy of the test current: ±10%
- resistance measurement time:
- with the selected resistive object type with the bidirectional current: 3 seconds
- with the selected inductive object type, dependant on the resistance
and inductance of the object: a few minutes (max. 10)
- dimensions: 295 x 222 x 95 mm
- weight: approx. 1,7 kg

Rated operational conditions:
- operation temperature: 0...+40°C
- storage temperature: -20...+60°C

MMR-620 microohmmeter conforms the following directives
or standards according to CE requirements.

Directive:
Low Voltage Directive (LVD) 73/23/EEC, 93/68/EEC.

Standards: 
EN 61010 - 1:2001 Safety requirements for electrical equipment for measurement, control and laboratory use. General requirements .
EN 61010 - 031:2002: Safety requirements for electrical equipment for measurement, control and laboratory use. Safety requirements for hand-held probe assemblies for electrical measurement and test.

Directive: 
Electromagnetic compatibility (EMC) 89/336/EEC, 92/31/EEC, 93/68/EEC.

Standards:
EN 61326:1997+A1:1998+A2:2001 Electrical equipment for measurement, control and laboratory use - EMC requirements.

Resistance measurement

- input impedance of the voltmeter: ≥200 kΩ