Precautions for All Safety Limit Switches
x
Unbalanced force must not be imposed on the actuator. Otherwise,
wear and tear on the actuator may result.
x
Make sure that the actuator does not exceed the OT (overtravel)
range, otherwise the Limit Switch may malfunction. When
mounting the Limit Switch, be sure to adjust the Limit Switch
carefully while considering the whole movement of the actuator.
x
The Limit Switch may soon malfunction if the OT is excessive.
Therefore, adjustments and careful consideration of the position of
the Limit Switch and the expected OT of the actuator are
necessary when mounting the Limit Switch.
x
Be sure to use the Limit Switch according to the characteristics of
the actuator.
If a roller arm lever actuator is used, do not attempt to actuate the
Limit Switch in the direction shown below.
x
Do not modify the actuator to change the OP.
x
In the case of a long actuator of an adjustable roller lever type, the
following countermeasures against lever shaking are
recommended.
1.
Make the rear edge of the object smooth with an angle of 15
q
to 30
q
or make it in the shape of a quadratic curve.
2.
Design the circuit so that no error signal will be generated.
3.
Use or set a switch that is actuated in one direction only.
(Also, set the switch for operation in one direction only.)
Operating Environment
x
These Switches are for indoor applications.
The Switches may fail if they are used outdoors.
x
Do not use the Switch in locations where toxic gases, such as H
2
S,
SO
2
, NH
3
, HNO
3
, and Cl
2
, may be present, or in locations that are
subject to high temperatures or humidity. Doing so may damage
the Switch due to contact failure or corrosion.
x
Do not use the Switches in the following locations.
·
Locations subject to severe temperature changes
·
Locations subject to high temperatures or condensation
·
Locations subject to severe vibration
·
Locations where the interior of the Protective Door may come into
direct contact with cutting chips, metal filings, oil, or chemicals
·
Locations where the Switch may come into contact with thinner or
detergents
·
Locations where explosive or flammable gases are present
Switch Contacts
Switch contacts can be used with both standard loads and
microloads, but once a contact has been used to switch a standard
load, it cannot be used for a load of a smaller capacity.
Doing so may result in roughening of the contact surface and contact
reliability may be lost.
Storing Switches
Do not store the Switch in locations where toxic gases, such as H
2
S,
SO
2
, NH
3
, HNO
3
, and Cl
2
, may be present, or in locations that are
subject to, excessive dirt, excessive dust, high temperature, or high
humidity.
Other Precautions
x
When attaching a cover, be sure that the seal rubber is in place and
that there is no foreign material present. If the cover is attached
with the seal rubber out of place or if foreign material is stuck to the
rubber, a proper seal will not be obtained.
x
Perform maintenance inspections periodically.
x
Use the Switch with a load current that does not exceed the rated
current.
x
Do not use any screws to connect the cover other than the
specified ones. The seal characteristics may be reduced.
Dog Design
Operating Speed, Dog Angle, and Relationship with
Actuator
Before designing a dog, carefully consider the operating speed and
angle of the dog and their relationship with the shape of the actuator.
The optimum operating speed (V) of a standard dog at an angle of 30
q
to 45
q
is 0.5 m/s maximum.
Roller Lever Models
1.
Non-overtravel Dog
Dog
Dog
Incorrect
Correct
Roller
Roller
Dog
Install a stopper.
PT (Pretravel)
FP (Free position)
OP (Operating position)
OT (Overtravel)
80% of
rated OT
100% of
rated OT
TTP (Total travel position)
Distance to the optimum
setting range.
Optimum setting
range
Reference line
Correct
Stopper
Incorrect
Dog speed: 0.5 m/s max. (Standard Speed)
I
V max. (m/s)
y
30
q
0.4
0.8 (TT)
80% of totaltravel
45
q
0.25
60
q
0.1
60
q
to 90
q
0.05 (low speed)
Lever set vertically
φ
http://www.ia.omron.com/
C-2
(c)Copyright OMRON Corporation 2007 All Rights Reserved.
