08-10-2012, 10:59 AM
Magnetically Actuated Proximity Sensors
[attachment=35612]
Magnetically Actuated Proximity Sensors
offer Sensing Versatility
Magnetically actuated sensors are primarily designed for use on
cylinders manufactured with sensing capability (i.e. permanent magnet
on the circumference of the cylinder piston), but many of them can also
be used in other areas where the proximity to a magnetic field is to be a
criterion for producing electrical control signals.
Reed Switch
When the piston’s magnet enters the response travel range
of the sensor, the magnet’s field causes the contacts of the
reed switch inside the sensor to close, completing the circuit
path to illuminate the LED (if present) and activate the output
signal. When the magnet moves out of the response travel
range, the reed switch opens again; the LED extinguishes
and the output signal returns to its inactive (i.e. “off”) state.
Built-in protective circuits in a reed switch proximity sensor
include current limiting and RC surge suppression.
The reed switch is very sensitive to interference from other
nearby magnetic fields or electromagnets with field strength
greater than 0.16 mT (T = Tesla). If it is to be used in such
conditions, appropriate shielding must be installed.
Magnetically Actuated Proximity Sensors
When inductive loads are switched, a high voltage peak occurs when the
contacts open. For this reason, protective circuitry must be provided for the
proximity switch.
The protective circuitry may consist of either a suitable RC circuit or a
corresponding diode or varistor (see circuit diagrams). The electrical values of
these components depend on the downstream operating elements (e.g., relays,
etc.).
If a relay or auxiliary switch is to be shifted, specifications regarding the SME-1
and relay or auxiliary switch must be strictly observed.
Caution:
The inrush power of a relay or auxiliary switch is several (8-10) times greater
than the holding power. The inrush power should therefore be used as a
guideline.
[attachment=35612]
Magnetically Actuated Proximity Sensors
offer Sensing Versatility
Magnetically actuated sensors are primarily designed for use on
cylinders manufactured with sensing capability (i.e. permanent magnet
on the circumference of the cylinder piston), but many of them can also
be used in other areas where the proximity to a magnetic field is to be a
criterion for producing electrical control signals.
Reed Switch
When the piston’s magnet enters the response travel range
of the sensor, the magnet’s field causes the contacts of the
reed switch inside the sensor to close, completing the circuit
path to illuminate the LED (if present) and activate the output
signal. When the magnet moves out of the response travel
range, the reed switch opens again; the LED extinguishes
and the output signal returns to its inactive (i.e. “off”) state.
Built-in protective circuits in a reed switch proximity sensor
include current limiting and RC surge suppression.
The reed switch is very sensitive to interference from other
nearby magnetic fields or electromagnets with field strength
greater than 0.16 mT (T = Tesla). If it is to be used in such
conditions, appropriate shielding must be installed.
Magnetically Actuated Proximity Sensors
When inductive loads are switched, a high voltage peak occurs when the
contacts open. For this reason, protective circuitry must be provided for the
proximity switch.
The protective circuitry may consist of either a suitable RC circuit or a
corresponding diode or varistor (see circuit diagrams). The electrical values of
these components depend on the downstream operating elements (e.g., relays,
etc.).
If a relay or auxiliary switch is to be shifted, specifications regarding the SME-1
and relay or auxiliary switch must be strictly observed.
Caution:
The inrush power of a relay or auxiliary switch is several (8-10) times greater
than the holding power. The inrush power should therefore be used as a
guideline.