The 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.
The SR23 uses an infrared emitter and receiver positioned on opposite sides of a fixed fork. The label web passes between them, and the sensor detects changes in transmitted light between the label and its backing. This arrangement keeps the optical components aligned within one housing.
The 5 mm slot width provides clearance for thicker label constructions, while the 50 mm slot depth allows the detection point to reach in from the web edge. Check the combined thickness of the label and backing, including raised booklet sections, and leave clearance for movement through the slot.
Typical applications include detecting extended-content labels on pharmaceutical packaging lines, controlling label feed in food and cosmetics machinery, and supplying a position signal to print-and-apply equipment. The sensor detects the label on its backing before application.
The specified minimum label width and gap between labels range from 0.5 to 2 mm, depending on backing transparency. Detection at 0.5 mm therefore requires suitable material conditions; assess the actual label stock and smallest gap before selecting the sensor.
The SR23 has a maximum switching frequency of 12 kHz and a maximum response time of 40 µs. These describe the sensor’s electrical performance. Usable web speed also depends on label pitch, gap size, optical contrast and the machine controller’s ability to capture each signal.
Teach-in sets the switching threshold between the label and exposed backing. Static teaching acquires these two conditions separately using the SET push-button. Dynamic teaching acquires them as several labels move through the fork.
During dynamic acquisition, pass three to eight labels through the sensor at no more than 20 m/min. This speed limit applies to teaching; production speed requires a separate application check. The green READY and yellow OUTPUT indicators help operators assess setup and switching behaviour.
A remote SET input also supports configuration from the machine controls. Repeat teaching when changing label or backing materials, then check detection at the intended operating speed.
Choose the output type to match the controller input, then select an integral cable or detachable M8 connection. The four models below use infrared detection and include a remote SET input.
| Model | Order number | Output | Connection |
|---|---|---|---|
| SR23-2-IR-PH | 953161000 | PNP | Integral 2 m, four-wire cable |
| SR23-2-IR-NH | 953161020 | NPN | Integral 2 m, four-wire cable |
| SR23-5-IR-PH | 953161010 | PNP | M8 four-pin connector |
| SR23-5-IR-NH | 953161030 | NPN | M8 four-pin connector |
A PNP output supplies positive voltage to the controller input; an NPN output switches it towards 0 V. These are separate model variants, so check the existing wiring before ordering a replacement. For an M8 model, specify the mating cable length and straight or angled connector required.
The SR23 requires a 10–30 VDC supply and draws up to 30 mA excluding the output load. Maximum output current is 100 mA, with reverse-polarity and output short-circuit protection. The four connections carry supply voltage, 0 V, switching output and remote SET.
Current model listings specify an 11 × 25 × 64 mm metal/PBT housing, IP65 protection and an operating temperature range of −20°C to +55°C. Check the selected model’s dimensioned drawing, mounting position and cable clearance before installation. Assess exposure to cleaning chemicals and pressure washing separately when fitting the sensor to food or pharmaceutical equipment.
Illustrative timing check: a 1 mm gap travelling at 1 m/s passes the sensing point in 1 ms. A controller input filter longer than that pulse can miss the gap, even when the sensor detects it. Check input filtering and signal capture alongside the sensor response time.
The SR23 suits applications that need its 5 mm slot clearance for booklet or multilayer labels. For thinner label webs requiring faster switching, consider the Datalogic SR21 fork sensor: it has a 2 mm slot width, the same nominal 50 mm slot depth, a maximum switching frequency of 25 kHz and a maximum response time of 20 µs.
Choose SR21-IR for label detection or assess SR21-RG when the task involves detecting printed register marks on transparent film. Check material response, mounting and wiring before substituting either model; the higher switching frequency alone does not establish suitability.
Suitability depends on a detectable difference in infrared transmission between the label and backing. Supply samples for assessment when both are transparent or their optical properties are similar. If teaching cannot establish a stable distinction, a different sensing principle may be required.
The SR23 provides a switching signal as labels and gaps pass through its fork. Reading printed information or checking a label after application requires a separate inspection arrangement.
MarvelTech supplies industrial sensors and supports production-automation projects, equipment adjustments and maintenance. For an SR23 enquiry, provide the label and backing materials, maximum thickness, smallest label and gap dimensions, web speed, controller input type and available mounting space.
Include the required quantity, cable or connector preference, installation location and any existing sensor part number. Photos, drawings and label samples help assess the configuration. Request a quotation covering the selected sensor, connection accessories and any required installation or support, with availability, lead time and warranty terms confirmed for the order.
The Datalogic SR23 detects label edges and gaps on a moving label web in labelling, packaging and print-and-apply machines. It is particularly relevant to booklet and multilayer labels that need additional clearance through the fork. Selection depends on distinguishing the label from its backing using infrared light. Its switching signal supports feed control; it does not verify printed information or final label placement.
The SR23 has a 5 mm slot width and a nominal 50 mm slot depth, accommodating thicker label constructions. The 5 mm opening is not a permissible material-thickness specification: allow clearance for the backing, raised booklet sections and movement during feeding. Check the thickest part of the complete label assembly and whether the required detection point is reachable from the web edge.
Only when the label and backing produce a sufficient difference in infrared transmission. Clear-on-clear materials may provide too little optical contrast for stable teaching and detection. For these applications, assess the Datalogic SRX3 ultrasonic fork sensor, which uses ultrasound to distinguish material layers. Check its clearance, gap and speed requirements separately before treating it as a replacement.
The SR23 catalogue lists minimum label widths and gaps of 0.5–2 mm, so the 0.5 mm headline figure should not be treated as a universal design limit. Confirm the applicable minimum against the instruction manual supplied with the sensor and assess representative label stock. Sub-2 mm applications particularly need verification of material contrast, teaching and detection at production speed.
The SR23 offers a wider 5 mm slot for thicker labels, while the Datalogic SR21 fork sensor has a 2 mm slot and faster switching: up to 25 kHz compared with SR23’s 12 kHz. Both have a nominal 50 mm slot depth. Choose SR21-IR for label detection or assess SR21-RG for printed register marks on transparent film; check mounting and wiring before substitution.
The SR23 specifies a maximum switching frequency of 12 kHz and a maximum response time of 40 µs, but these figures do not establish a universal web speed. The shortest label or gap determines how briefly each condition reaches the sensor. Check that the controller can capture those pulses, accounting for input filtering, and validate operation with the actual material at the intended speed.
The SR23 supports static and dynamic teach-in through its SET push-button, with a remote SET input for setup through machine controls. Static teaching acquires the label and exposed backing separately. Dynamic teaching samples several moving labels at no more than 20 m/min. That limit applies to acquisition, not production. Repeat teaching after material changes and check switching at the intended operating speed.
SR23-2-IR-PH and SR23-5-IR-PH have PNP outputs; SR23-2-IR-NH and SR23-5-IR-NH have NPN outputs. The SR23-2 versions include an integral 2 m cable, while SR23-5 versions use an M8 four-pin connector. Match the output type to the controller input before selecting the connection. PNP and NPN are separate hardware variants, so changing a setting does not convert one into the other.
The SR23 requires a 10–30 VDC supply and a compatible PLC input for its selected PNP or NPN output. The output is rated up to 100 mA. For an M8 model, specify a matching four-pin cable with the required length and connector orientation. Check the pin assignment, remote SET wiring and label-versus-gap output logic before reusing an existing machine connection.
The SR23 can serve food and pharmaceutical labelling machinery within its operating limits of −20°C to +55°C and IP65 protection. Suitability for the industry does not establish suitability for every cleaning zone. Assess cleaning pressure, water temperature, chemicals and connector exposure separately. Select the mounting position to keep the optical path accessible for cleaning and clear of adhesive residue or label debris.
Provide label and backing samples or specifications, maximum combined thickness, smallest label and gap dimensions, web speed, controller input type and available mounting space. Include quantity, cable preference and the existing sensor code for replacements. Photos or drawings help identify installation constraints. If commissioning or maintenance is required, include it in the enquiry alongside Marveltech’s industrial automation services so the quotation defines the required scope.
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 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.
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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