ESD Continuous Wrist Band Monitors

From £69.00 Excl. VAT

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Datasheet:

Wrist straps are still the first and best line of defence against ESD but they must always be tested to ensure that they are installed and working correctly. Continuous monitors eliminate the possibility of a component being exposed to ESD during the time period that the wrist strap was not working properly.

CAPACITANCE MONITORS – HOW THEY WORK

Constant CAPACITANCE monitors make use of the fact that a person can be thought of as one plate of a capacitor with the other plate being ground. The ground and the person are both conductors and they are separated (sometimes) by an insulator (shoes, mats, carpet, etc.) thus forming a capacitor. The combined resistance of the wrist strap and person forms a resistor so that the total circuit is a simple RC circuit. A tiny AC current applied to this circuit will cause a displacement current in the capacitance flow to ground providing a simple way to make sure the person (capacitor) resistor (wrist strap) and coil cord are all hooked up. Any break in this circuit results in a higher impedance that can be used to trigger an alarm.

DUAL-WIRE RESISTANCE MONITORS – HOW THEY WORK

Dual-wire RESISTANCE monitors use the concept of providing a second path to ground (without relying on the capacitor above) and then applying a tiny DC current. It is easy to measure the DC resistance of the circuit and alarm if that resistance goes too high (open circuit) or too low (the safety resistor is shorted). However; Dual wire monitors require two wires to work. This means that the wearer must wear a special dual wire twin conductor wrist strap and coil cord which are more expensive than the standard single wire wrist straps.

Should any part of the ESD system fail a red LED indicator will illuminate and a buzzer sound.

That part of the system should then be checked using the appropriate test equipment before continuing.

Capacitance Constant Monitor:

  • Works with a standard wrist strap and cord and has a body mass adjustment for individual user set up:
  • Constant monitoring of the earth to ground connection.
  • Constant monitoring of the work mat to earth connection.
  • Constant monitoring of the wrist strap connection.

Resistance Constant Monitor:

  • ONLY Works with a dual wrist strap and cord and automatically enters standby mode when the wrist strap is removed.
  • Indicates high or low fail for the users wrist strap.
  • Constant monitoring of the earth to ground connection.
  • Constant monitoring of the work mat to earth connection
  • Constant monitoring of the wrist strap connection.
  • Wrist strap and cord not supplied.

Additional information

Weight 12 kg

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