The Datalogic SRF Fork Sensor is a photoelectric fork sensor for small-part detection, edge positioning and object counting in packaging machinery, automotive assembly and automated production lines. Four fork widths, from 30 to 120 mm, and separate LED and laser models allow selection according to the available clearance, target size and switching-speed requirement.
The SRF detects objects that interrupt a light beam between an emitter and receiver built into the same metal housing. This fixed optical alignment removes the need to position two separate sensing components, making the fork format useful for defined detection points in automated machinery.
Typical tasks include counting components in a feed mechanism, detecting a moving edge and confirming part presence before an assembly or packaging operation. The target must pass through the sensing beam with sufficient mechanical clearance.
Select the opening around the target path, mounting space and smallest feature requiring detection. A wider opening accommodates a larger material path, but the minimum detectable object also changes with fork width.
| Fork width | Slot depth | Approximate body dimensions | LED minimum object | Laser minimum object |
|---|---|---|---|---|
| 30 mm | 34 mm | 10 × 50 × 59 mm | 0.30 mm | 0.05 mm |
| 50 mm | 54 mm | 10 × 70 × 79 mm | 0.50 mm | 0.08 mm |
| 80 mm | 54 mm | 10 × 100 × 79 mm | 0.50 mm | 0.10 mm |
| 120 mm | 54 mm | 10 × 140 × 84 mm | 0.80 mm | 0.15 mm |
These are manufacturer-specified detection values, not dimensional measurement accuracy. Validate the actual target at its operating position and speed, particularly near the minimum size or where material transparency changes the received light.
LED versions use 640 nm red emission, with a specified response time of 333 µs and switching frequency of 1.5 kHz. Each fork width has separate PNP and NPN versions. For example, SRF-50-5-P is the 50 mm PNP model, while SRF-50-5-N is its NPN equivalent.
Laser versions use 650 nm red emission, with a specified response time of 100 µs and switching frequency of 5 kHz. They detect smaller features than the corresponding LED versions. The documented ordering range lists PNP laser models: SRF-L-30-5-P, SRF-L-50-5-P, SRF-L-80-5-P and SRF-L-120-5-P.
Both emission types have sensitivity adjustment and selectable Light/Dark operation. Choose the electrical output when ordering; the operating-mode adjustment does not convert a PNP sensor into an NPN sensor.
SRF sensors require a 10–30 V DC supply and use an M8 three-pole connector. Maximum consumption, excluding the output load, is 35 mA for LED models and 20 mA for laser models. The maximum output current is 200 mA.
The documented connections are pin 1, brown, for positive supply; pin 3, blue, for 0 V; and pin 4, black, for the switching output. Match the sensor to the PLC input: PNP supplies positive voltage to the input, while NPN switches the output towards 0 V.
Light operation activates the output when the receiver sees the beam; Dark operation activates it when the beam is interrupted. Adjust sensitivity using representative targets and check both object-present and object-absent states.
For counting applications, check the controller’s input filtering and acquisition speed against the shortest object and gap durations. The sensor’s switching frequency alone does not establish the achievable production-line throughput.
A machine checking a 0.20 mm opaque wire across a 50 mm opening would favour SRF-L-50-5-P for evaluation. Its specified minimum detectable object is 0.08 mm, whereas the 50 mm LED model is specified at 0.50 mm. Confirm detection with the actual wire, movement and controller settings before approving the configuration.
The series has a metal housing, glass lenses and IP67 protection, with an operating temperature range of −10°C to +60°C without freezing. Check the cleaning method, chemical exposure and connector protection separately when selecting a sensor for wet machinery.
Leave room for the target’s movement, cable connection and adjustment controls. If the material cannot pass through the fork without contact, a different sensor geometry is needed. SRF is a process-detection sensor and is not suitable for personnel-protection applications.
Suitability depends on whether the label and backing produce a sufficient change in received light. A wide fork opening alone does not establish reliable label-gap detection, particularly with transparent materials. Provide samples of both the label and liner for assessment.
For a label web that fits a 2 mm slot, consider the Datalogic SR21 fork sensor. SR21-IR is designed for label detection and specifies a 20 µs response time and 25 kHz switching frequency, compared with 100 µs and 5 kHz for SRF laser models. SR21 uses an M8 four-pole connection, so replacing an SRF requires a mounting and wiring review.
Select an M8 three-pole connection lead with the required length and connector orientation. Catalogue accessories include 3 m and 5 m leads with straight or angled connectors. Specify the cable separately in the enquiry and confirm what is included in the quotation.
Provide the complete model designation and order number from the sensor label. Match the fork width, emission type, output, mounting dimensions and connector clearance; a shared fork width does not establish that two versions are interchangeable.
MarvelTech can review the detection task, mounting arrangement and controller requirements to recommend an SRF configuration and discuss machine integration. The quotation depends on the selected model, quantity, connection accessories and any requested integration work. Ask for confirmation of availability, lead time, warranty terms and support scope for the proposed supply.
Request an SRF quote with the target material and smallest feature, required fork clearance, machine speed and object spacing, PLC input type and quantity. Include a photograph or drawing of the detection point and the full sensor reference when replacing an existing unit.
The SRF suits part-presence checks, component counting and edge detection where the target passes between the fork’s emitter and receiver. This arrangement keeps the optical components aligned within one housing. For packaging or assembly machinery, check that the target interrupts the beam sufficiently and has clearance throughout its movement. Applications requiring access from only one side need a different sensor arrangement.
Choose the fork width around the target’s full movement envelope, allowing clearance for vibration and positioning variation. Also check slot depth: the 30 mm model provides 34 mm, while the 50, 80 and 120 mm models provide 54 mm. Width determines clearance across the opening; depth determines how far the detection point can reach in from the material’s edge.
Choose laser when the smallest feature falls below the corresponding LED model’s detection limit. For a 50 mm opening, SRF-L-50-5-P specifies 0.08 mm resolution, compared with 0.50 mm for SRF-50-5-P. These figures describe minimum detectable object size, not dimensional measurement accuracy. Assess the actual target’s orientation, transparency and movement, particularly when operating near the specified limit.
LED models specify a 333 µs response time and 1.5 kHz switching frequency; laser models specify 100 µs and 5 kHz. Achievable counting speed also depends on how long each object blocks the beam and how long the gap exposes it. Check both durations against the sensor response and the controller’s input filtering and acquisition timing before selecting a model.
SRF may detect labels when the label and exposed backing produce a sufficiently distinct received-light level. Transparent labels on transparent backing need particular scrutiny because optical separation can be weak. For this application, consider the Datalogic SRX3 ultrasonic label sensor, which uses ultrasound. Check its slot clearance and speed limits against the application, and assess representative label-and-liner samples.
SRF LED models have separate PNP and NPN versions, while the manufacturer’s ordering table lists PNP laser versions. For example, SRF-50-5-P and SRF-50-5-N are the 50 mm LED options; SRF-L-50-5-P is the laser option. Match the output to the controller input when ordering. Light/Dark selection changes the switching condition; it does not change PNP into NPN.
SRF requires a 10–30 V DC supply and an M8 three-pole mating cable. Its maximum output current is 200 mA, so check the connected load as well as the controller’s input type. Specify cable length, straight or angled connector orientation, and installation conditions in the enquiry. Confirm whether the connection lead is included in the quoted supply.
SRF uses local sensitivity and Light/Dark adjustment trimmers, so configuration software is not required for sensor setup. Light operation activates the output when the receiver sees the beam; Dark operation activates it when the beam is interrupted. Set sensitivity using representative targets, then verify switching with the target present and absent at the intended operating speed.
The SRF has a metal housing, glass lenses, IP67 protection and a specified operating temperature range of −10°C to +60°C. Check cleaning chemicals, water-jet exposure and connector sealing separately when assessing a wet installation. Keep the optical surfaces accessible for cleaning: contamination across the beam path can affect detection even when the housing remains protected.
A matching fork width is only one compatibility check. Compare the complete model designation, emission type, minimum detectable object, output type, mounting drawing and connector clearance. Moving from LED to laser also changes response characteristics and may require controller timing or sensitivity adjustments. Record the existing settings and verify the replacement with the machine’s actual targets before returning it to production.
Include the target material, smallest feature, required fork clearance, maximum speed, minimum object spacing, controller input type and quantity. Add installation photographs or drawings, cable requirements and the full sensor reference for replacements. Use the SRF order enquiry form to request model selection and pricing, identifying any integration assistance required and asking for availability and lead-time confirmation.
The Datalogic SRX3 Ultrasonic Fork Sensor detects transparent, opaque and metallic-ink labels in packaging, labelling and print-and-apply machinery, including clear labels on clear backing. Its ultrasonic sensing method distinguishes labels from their backing without relying on optical contrast and supports single- and double-film detection after application-specific setup.
See DetailsThe Datalogic SR23 Fork Sensor is a photoelectric label sensor for label-edge and gap detection in labelling machines, packaging lines and print-and-apply systems. Its 5 mm fork slot accommodates booklet and multilayer label formats, while a switching frequency of up to 12 kHz supports fast label-feed control.
See DetailsThe Datalogic SR21 Fork Sensor is a photoelectric label sensor for label positioning and print register-mark detection in packaging, labelling and print-and-apply machinery. With a maximum response time of 20 µs and switching frequency up to 25 kHz, it provides fast detection signals as material passes through its 2 mm fork slot.
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