E2EM E2EM
JMAINTENANCE AND INSPECTION
Periodically perform the following checks to ensure stable
operation of the Proximity Sensor over a long period of time.
1. Check for mounting position, dislocation, looseness, or
distortion of the Proximity Sensor and sensing objects.
2. Check for loose wiring and connections, improper contacts,
and line breakage.
3. Check for attachment or accumulation of metal powder or
dust.
4. Check for abnormal temperature conditions and other
environmental conditions.
5. Check for proper lighting of indicators (for models with a set
indicator.)
Never disassemble or repair the Sensor.
JENVIRONMENT
Water Resistance
Do not use the Proximity Sensor underwater, outdoors, or in the
rain.
Operating Environment
Be sure to use the Proximity Sensor within its operating ambient
temperature range and do not use the Proximity Sensor outdoors
so that its reliability and life expectancy can be maintained.
Although the Proximity Sensor is water resistive, a cover to
protect the Proximity Sensor from water or water-soluble
machining oil is recommended so that its reliability and life
expectancy can be maintained.
Do not use the Proximity Sensor in an environment with chemical
gas (e.g., strong alkaline or acid gasses including nitric, chromic,
and concentrated sulfuric acid gases).
JCONNECTING LOAD TO DC 2-WIRE
SENSOR
Refer to the following before using DC 2-wire Proximity Sensors.
Surge Protection
Although the Proximity Sensor has a surge absorption circuit, if
there is any machine that has a large surge current (e.g., a motor
or welding machine) near the Proximity Sensor, connect a surge
suppressor to the machine.
Countermeasures Against Leakage Current
Connect a bleeder resistor as the bypass for the leakage current
so that the current flowing into the load will be less than the load
reset current.
Bleeder resistor R
Load
VS
Refer to the following to calculate the bleeder resistance and the
allowable power of the bleeder resistor.
Leakage Current
When the Proximity Sensor is OFF, the Proximity Sensor has
leakage current. In this case, the load is imposed with a small
voltage and the load may not be reset. Before using the Proximity
Sensor, make sure that this voltage is less than the load reset
voltage.
R≦VS/(iR-- i OFF)(kΩ)
P>V
S2/R (mW)
P: The allowable power of the bleeder resistor. (The actual
power capacity of the bleeder resistor must be at least a few
times larger than the allowable power of the bleeder resistor.)
iR: Leakage current of the Proximity Sensor (mA)
iOFF: Load reset current (mA)
It is recommended that 15 kΩmax./450 mW min. for 12 VDC and
30 kΩmax./0.1 W min. for 24 VDC be used.
Inrush Current
A load that has a large inrush current (e.g., a lamp or motor) will
damage the Proximity Sensor, in which case connect the load to
the Proximity Sensor through a relay.