A photoelectric switch is a sensor device that uses optical principles for object detection, lt mainly perceives the position and presence of objects by emitting a beam of light and detecting the state of the received beam. Photoelectric switches typically consist of a light source, photoelectric sensors, and signal processing components.
Throuht-beam type
Through-beam bype photoelectric switch is designed that via the light beam between opposite-mounted transmitter and receiver, the object passing through these two devices will interrupt the light beam and start the receiver. (Fig.R1)
Diffuse type
Diffuse reflection type photoelectric switch integrates the transmitter and the reciver. Light reflected by the photoelectric switch is reflected back to the receiver by the detected object. (Fig.R2)
Retroreflective type
Retroreflective type photoelectric switch also integrates the transmitter and the receiver, Its difference from other models is that reflecotr is used to relfect light to the photoelectric switch. Though the object between the photoelectric switch and reflector can reflect the light, it is much less efficient than the reflector so as to cut down reflected light. (Fig.R3)
Convergence reflection type (condensation type)
The working principle of convergence reflection type photoswitch is similar to that of direct reflection type one, while its projector and light receiver focus on boject distance, only when the object presents to the focus can the photoswitch actuate.(Fig.R4)
| Model | GT18 | |||
| Dimension |  |
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| Sense distance | 10cm~30cm | |||
| Diffuse type | DC10~30VDC | NPN | NO | GT18-3A10NA |
| NC | GT18-3A10NB | |||
| NO+NC | GT18-3A10NC | |||
| PNP | NO | GT18-3A10PA | ||
| NC | GT18-3A10PB | |||
| NO+NC | GT18-3A10PC | |||
| AC90~250VAC | NO | GT18-2A10LA | ||
| NC | GT18-2A10LB | |||
| Relay | ||||
| Sense distance | 2m | |||
| Reflection-type | DC10~30VDC | NPN | NO | GT18-3B2NA |
| NC | GT18-3B2NB | |||
| NO+NC | GT18-3B2NC | |||
| PNP | NO | GT18-3B2PA | ||
| NC | GT18-3B2PB | |||
| NO+NC | GT18-3B2PC | |||
| AC90~250VAC | NO | GT18-2B2LA | ||
| NC | GT18-2B2LB | |||
| Relay | ||||
| Sense distance | 5m | |||
| Through-beam type | DC10~30VDC | NPN | NO | GT18-3C5NA |
| NC | GT18-3C5NB | |||
| NO+NC | GT18-3C5NC | |||
| PNP | NO | GT18-3C5PA | ||
| NC | GT18-3C5PB | |||
| NO+NC | GT18-3C5PC | |||
| AC90~250VAC | NO | GT18-2C5LA | ||
| NC | GT18-2C5LB | |||
| Relay | ||||
| Output voltage peak | DC:200mA、AC:300mA | |||
| Consumption current | DC<15mA、AC<10mA | |||
| Standard detected object | DC<2ms、AC<20ms | |||
| Repeatability | 2°~10° | |||
| Response frequency | Transparent oropaque body | |||
| Ambient temperature | -25℃ - +55℃ | |||
| Ambient brightness | Sunlight below 10000LX, incandescent lamp below 30000LX | |||
| Shell material | ABS plastic | |||
| Protection grade | IP54 | |||
