Load Cell Surge Protector

Load cell surge protector
Model IQ640 
is a Surge Protector arrester for Load Cells and Weighing Systems to protect signal, supply and shield lines.

With unique Triple Stage surge protection circuitry the IQ640 handles higher transients than protectors based only on diodes.

Stage 1 comprises 3-terminal gas discharge tubes providing superior differential and common mode protection against conducted transients than surge protectors based on 2-terminal gas discharge tubes.
Stage 2 comprises current limiting fusible series surge resistors which in a rare case of extreme lightning or surge event will resort to a fail safe operation. This effectively disconnects the line from sensitive electronic equipment.
Stage 3 comprises a low capacitance over voltage diode clamp array. The diode array clamps fast transients to a safe level until the gas discharge tubes turn on.

Simple to fit between load cells or junction boxes and weighing amplifiers, IQ640 may also be installed at both ends of the system for maximum surge protection.

Applications include:
  • Cranes
  • Load pins
  • Load cells
  • Tension cells
  • Belt weighers
  • Strain gauges
  • Weigh bridges
  • Protects against over voltage and high power impulse currents
  • Protects signal, supply and shield lines
  • High power triple stage surge protection
  • Ground clamp provided on the exterior of the enclosure
  • Suitable for AC or DC load cell excitation voltages
  • IP65 environmental protection rating
  • Supports 4 or 6 wire load cells
  • Clear lid for easy fault finding
  • Shielded 6-wire connection to the load cell instrumentation
  • Cage clamp wire connectors
  • 1 year limited warranty
General:Model IQ640
Dimensions160 x 80 x 55mm / 6.3 x 3.15 x 2.17”
SealingTongue and groove with Neoprene seal
MaterialPolycarbonate (grey base, clear lid)
Protection RatingIP65
Stage 1 clamping voltage± 90V
Stage 2 series resistance<= 1 Ohm
Stage 3 clamping voltage± 24V
Maximum excitation voltage (symmetrical to ground)22Vac or 32Vdc
Leakage current at 20V<10uA
Maximum surge current5kA (8/20uS)
Main earth connectionExternal M8 Stud
Connections:Input/Output/Sense + Earth
Connector Ratings:(Cage clamp wire connectors)
Conductor cross section solid min0.2mm2
Conductor cross section solid max2.5mm2
Conductor cross section stranded min0.2mm2
Conductor cross section stranded max1.5mm2
Conductor cross section solid min with ferrule 0.25mm2
Conductor cross section solid max with ferrule 1.5mm2
Wire stripping length7.5mm
Gland Ratings:IP65
Clamping/sealing range4-8mm / 0.157-0.314” diameter
Environmental Conditions:
Operating temperature-20°C to 60°C (-4°F to 140°F)
Storage temperature-40°C to 80°C (-40°F to 176°F)
Operating and storage humidity<95% RH (non-condensing)

IQ640 Weigh system over voltage and high current arrester

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