omron FAQ

Frequently Asked Questions for Omron Fiber Sensors

Omron 3/5/2019

Question

When using a Fiber Unit mounted to a movable part, are there models that are less affected by repetitive bending?

Answer

Seven models are recommended: E32-T11 Fiber Unit, E32-T21, E32-T22B, E32-D11, E32-D21, E32-D21B, and E32-D22B. (These have a bending radius of R4.)

Explanation: The allowable bending radius of most Fiber Units is 25 mm minimum. Only the seven models listed above have an allowable bending radius of 4 mm. The fiber flexing characteristics have a strong relationship with the bare fiber diameter (see note 1). A bending radius that is 3 times or less the diameter exerts excessive force on the fiber and reduces the optical characteristics (see note 2 on light intensity).

Model Bare fiber diameter Flexing resistance data (light intensity retention, see note 3)
E32-T11
E32-D11
16 x 0.265 dia. Value after flexing 1,000 times at a bending radius of 4 mm (with no change)/Value after flexing 1,000,000 times (approx. 80%)
E32-T21
E32-T22B
E32-D21
E32-D21B
E32-D22B
4 x 0.25 dia. Value after flexing 1,000 times at a bending radius of 4 mm (with no change)/Value after flexing 1,000,000 times (approx. 85%)
E32-TC200
E32-DC200
1 x 1 dia. Value after flexing 1,000 times at a bending radius of 5 mm (approx. 95%)

Note:

1.Flexible Fiber Units (E32-[][]R) have an allowable bending radius of 1 mm, but do not handle repetitive bending well, so they should not be mounted on movable parts.

2.The light intensity of a Through-beam model is reduced to 50%, which reduces the sensing distance by about 30%.

3.

 Omron Fiber Sensors FAQ

The Fiber Units listed above have a structure that strongly withstands the bending radius R by using fibers with ultra-small diameters.

Note:Flexible Fiber Units (E32-[][]R) have an allowable bending radius of 1 mm, but do not handle repetitive bending well, so they should not be mounted on movable parts.

Question

What's the difference between a Reflective Fiber Unit and a Coaxial Reflective Fiber Unit?

Answer

The sensing surfaces of the Fiber Units differ as shown below. Each is used for a different type of application.

Omron Fiber Sensors FAQ

The differences in the sensing methods are given in the following table.

Sensing method Features and other information
Reflective models
(E32-DC200 and others)
Used for detecting the presence of ordinary workpieces.
Various Sensing Head shapes, sensing distances, etc., are available for specific applications.
The operating range depends on the set direction (see note) of the Fiber Head.
Coaxial reflective models
(E32-CC200, E32-D32, E32-D32L, E32-C31, E32-C41, E32-C42)
Used for workpiece positional detection.
The operating range depends on the set direction of the Fiber Head.
(This is because a fiber for the Receiver is placed near the fiber for the Emitter.)
Models other than the E32-CC200 and E32-D32L can be used as a small-spot reflective models when combined with a small-spot lens (E39-F3A, E39-F3A-5, E39-F3B, and E39-F3C).

Note:The set directions for the Fiber Head are ꝏ and 8.

Question

Can a Photoelectric Sensor with an Optical Fiber be used in an explosion-proof area?

Answer

Everything except the Amplifier Unit can be used in an explosion-proof area.

Explanation: A Photoelectric Sensor with an Optical Fiber has no electrical parts, and it can thus be used even in hazardous, explosion-proof areas. However, the lens, the case, and the fiber covering are made of plastic, so they must be free from corrosion or deterioration (fogging) due to contact with solvents.

As long fiber lengths are commonly used in explosion-proof areas, E32-T17L Fiber unit (standard fiber length: 10 m) is recommended.

Question

Which hole of the Amplifier Unit can the Through-beam Fiber Unit be inserted into?

Answer

It makes no difference which hole it is inserted into, because there is no distinction between the two fibers for a Through-beam Fiber Unit.

With a Coaxial Diffuse-reflective Fiber Sensors (such as the E32-C31), the holes that the fibers are inserted into are set for the receiver and emitter.