What Is a Fiber Optic Amplifier? Types and Selection Criteria
A fiber optic amplifier is the fiber optic sensor unit that sends light into a sensor fiber cable, evaluates the returning light and switches an output at the set threshold.
A fiber optic amplifier is the electronic unit that sends light into a sensor fiber cable, evaluates the intensity of the light returning through the fiber and switches an output at the set threshold. The amplifier is the brain of a fiber optic sensor: the light source, receiver, adjustment and output circuit are in this housing. It is used to detect small parts and objects in tight machine spaces. Since only a thin fiber end goes to the sensing point, the amplifier is mounted in the panel or at an accessible place on the machine.
Types
- Standard (potentiometer-adjusted) amplifier: Sensitivity is set with the adjuster on the housing (Isıso IEX-NA11, IEX-NA41).
- Digital amplifier: The threshold is set with buttons, and the same setting is easier to repeat across several amplifiers (Isıso OPOF50-B60-A0, OPOF50-B60-A2).
In both types the output is an NPN or PNP transistor.
Catalog models
| Model | Adjustment | Output | Housing | Sensing distance |
|---|---|---|---|---|
| Isıso IEX-NA11 | Standard | NPN NO+NC | B60 | 50 mm |
| Isıso IEX-NA41 | Standard | PNP NO+NC | B60 | 50 mm |
| Isıso OPOF50-B60-A0 | Digital | NPN NO+NC | B60 | 50 mm |
| Isıso OPOF50-B60-A2 | Digital | PNP NO+NC | B60 | 50 mm |
Values are taken from the product names; according to the catalog attribute the supply voltage is 10–30 V DC.
Selection criteria
- Output type: A PNP amplifier suits PLC inputs whose common is 0 V (positive logic), an NPN amplifier suits inputs whose common is +24 V (negative logic).
- NO and NC output: All amplifiers in the catalog have both outputs; use the signal you need, closing (NO) or opening (NC) when the object arrives.
- Adjustment: A standard amplifier is enough for fixed detection on a single machine. On lines where the threshold changes often or the same setting must be applied to many amplifiers, choose a digital amplifier.
- Fiber cable compatibility: The amplifier does not detect without a fiber cable. The fiber's end design must fit the amplifier; choose both from the same manufacturer's system.
- Sensing distance: The distance is the value the amplifier and fiber cable give together; through-beam fiber detects farther than diffuse reflective fiber.
- Supply: The 10–30 V DC supply can be taken from a 24 V DC control circuit.
Common mistakes
- Mixing up NPN and PNP: An amplifier with the wrong output type seems to work, but the PLC input receives no signal.
- Treating the amplifier as a complete sensor: Order the amplifier and the fiber cable together.
- Locking the fiber before it is fully seated: Light is lost and detection becomes unstable.
- Ignoring ambient light and shiny backgrounds: With diffuse reflective fiber, light returning from a shiny surface behind the object can switch the output even when no object is present.
Brands in the catalog
The Fiber Optic Amplifiers category has 4 active products, all from Isıso: 2 standard and 2 digital amplifiers. The M4 and M6 through-beam and diffuse reflective fibers used with these amplifiers are in the Sensor Fiber Optic Cables category. For the guide covering amplifier and fiber selection together, see the Fiber Optic Sensors and Accessories category.
Frequently asked questions
Does a fiber optic amplifier work on its own?
No. The amplifier generates and evaluates the light, but the fiber cable carries the light to the sensing point. A compatible sensor fiber cable is used with it.
What is the difference between a digital and a standard fiber optic amplifier?
A standard amplifier's sensitivity is set with an adjuster, a digital amplifier's with buttons. A digital amplifier makes work easier on lines where the threshold changes often or many amplifiers run with the same setting.
Should I choose an NPN or a PNP fiber optic amplifier?
Check your PLC input card. Use a PNP amplifier on inputs whose common is 0 V, and an NPN amplifier on inputs whose common is +24 V.
Is a fiber optic amplifier used for data transmission?
No. This amplifier is a sensing device; it is not the same product as the signal amplifiers used on communication fibers.