Technical Data · Publication 42C-TD001 · Rockwell Automation

Allen-Bradley Bulletin 42C Cylindrical Photoelectric Sensors — Technical Data

Complete specifications, catalog-number breakdowns, sensing-mode data, and dimensional drawings for the Allen-Bradley Bulletin 42C cylindrical photoelectric sensor family — 12 mm metal (42CF), 18 mm plastic (42CA), 18 mm metal (42CM), and 18 mm stainless steel (42CS) barrel styles. Mirrored from Rockwell Automation Publication 42C-TD001A-EN-P (October 2018).

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42C-TD001 Publication
42C Bulletin
12 mm and 18 mm Barrel Diameters
10…30V DC Supply Voltage

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Specifications

Sensing Modes & Performance

Sensing modes offered Retroreflective, polarized retroreflective, standard diffuse, fixed / adjustable background suppression, transmitted beam (thru-beam); laser variants on 42CM
Max range (retro) 42CA up to 7.2 m; 42CM up to 4 m; 42CS available with clear-object detection
Max range (diffuse) 42CA up to 1 m; 42CF 100…300 mm; 42CM up to 400 mm (laser up to 300 mm)
Max range (thru-beam) 42CA up to 16 m; 42CF 2 m; 42CM up to 50 m (infrared or laser variants)
Light sources Visible red 660 nm, infrared 880 nm, Class 1 laser 650 nm (42CM laser models)
Response time 0.5 – 2 ms typical (fastest on background-suppression and diffuse)

Electrical

Operating voltage 10…30V DC
Current consumption 30 mA max (42CS: 35 mA max)
Load current 100 mA
Output types NPN / PNP discrete; light-operate / dark-operate selectable on most models
Output function Light and dark operate (complementary outputs on many models)
Leakage current 0.1 mA (DC) max on 42CA; <10 µA on 42CM; 10 µA on 42CS
Protection Short-circuit, reverse-polarity, false-pulse, and overload protection

Mechanical

Barrel sizes 12 mm metal (42CF, M12×1), 18 mm plastic (42CA, M18×1), 18 mm metal (42CM, M18×1), 18 mm stainless (42CS, M18×1)
Housing material 42CA: polybutylene terephthalate (PBT); 42CF: nickel-plated brass; 42CM: nickel-plated brass; 42CS: 316L stainless steel with laser-etched markings
Lens material PMMA (acrylic) standard; laser and clear-object variants per spec
Connection options 2 m integral PVC cable (suffix -A2) or 4-pin DC micro (M12) QD pigtail (suffix -D4)
Sensitivity adjustment None, single-turn potentiometer, push-button teach, or ferromagnetic teach (42CS)
Supplied accessories Two fastener nuts (12 or 18 mm depending on barrel); 42CS ships with stainless teach rod

Environmental

Operating temperature -25…+70 °C (-13…+158 °F) — 42CA/CF/CM; 42CS extended: -25…+85 °C
Relative humidity 5…95% (non-condensing)
Enclosure type rating IP67 standard; 42CS adds IP69K, ECOLAB, and Johnson Diversey wash-down approvals
Shock 30 g, 11 ms pulse (42CA / CM), 1 ms pulse (42CF / CS), IEC 60947-5-2
Vibration 10…55 Hz, 1 mm amplitude, IEC 60947-5-2
Ambient light immunity 3000–5000 lux incandescent (42CS: 10,000 lux sunlight)

Catalog Number Format

How to read an Allen-Bradley 42C catalog number. Each position encodes a specific configuration attribute.

Position
Meaning
Example
42
Bulletin prefix — cylindrical photoelectric sensor family
42
C{A|F|M|S}
Barrel material / size (CA = 18 mm plastic, CF = 12 mm metal, CM = 18 mm metal, CS = 18 mm stainless steel)
CM = 18 mm metal barrel
-{U|P|D|B|R|E|D8}
Sensing mode (U = retroreflective, P = polarized retro, D = diffuse, B = background suppression, R = receiver thru-beam, E = emitter thru-beam, D8 = laser diffuse)
D = standard diffuse
Range code
Sensing-distance code (e.g., 1 = short range, 2 = extended range, letter suffix differentiates adjustment type)
1MPA = 100 mm diffuse / potentiometer / PNP
Output
Output type (NA / MNA = NPN no-adjust; PA / MPA = PNP no-adjust; NAJ / PAJ, NBC / PBC = variant adjust/output combos)
MPA = PNP output, no adjustment
-D4 or -A2
Connection style (-D4 = 4-pin M12 micro QD, -A2 = 2 m PVC cable)
-D4 = M12 quick-disconnect

Certifications & Compliance

c-UL-us Listed CE Marked (all applicable EU directives) IEC 60947-5-2 compliance IP67 enclosure rating (all barrels) IP69K enclosure rating (42CS stainless) ECOLAB wash-down compatibility (42CS) Johnson Diversey wash-down compatibility (42CS) Class 1 laser safety — IEC 60825-1 (42CM laser models) RoHS compliant

Document Contents

Full PDF covers the following topics in detail:

  • Four barrel families described in dedicated sections: 42CA (18 mm plastic), 42CF (12 mm metal), 42CM (18 mm metal), 42CS (18 mm stainless)
  • Per-family features, available sensing modes, and laser-model details
  • Specification tables — electrical, mechanical, environmental, optical characteristics
  • Product-selection tables listing every catalog number with sensing mode, range, light source, output type, and adjustment
  • User-interface / LED tables describing power, output, and margin indicator states
  • Wiring diagrams for cable and quick-disconnect variants, NPN and PNP outputs, thru-beam emitter and receiver
  • Approximate dimensions in mm (in.) for every barrel and connection style
  • Typical response curves — operating margin vs. distance, beam pattern diagrams, minimum detectable object curves
  • Cordsets, mounting brackets, and reflector accessory tables

Frequently Asked Questions

Which 42C barrel should I choose — 42CA plastic, 42CF 12 mm, 42CM 18 mm metal, or 42CS stainless?
Pick 42CA (18 mm plastic, PBT housing) for general-purpose factory automation where cost matters and chemical exposure is moderate. Pick 42CF (12 mm nickel-plated brass) when panel real estate is tight or vibration is high. Pick 42CM (18 mm metal) for heavy industrial ranges, laser precision, or when you need transmitted beam up to 50 m. Pick 42CS (18 mm 316L stainless steel) for food, beverage, pharma, and other IP69K / ECOLAB / Johnson Diversey wash-down environments.
Which sensing modes are available on the Bulletin 42C family?
The 42C family covers the full photoelectric-sensing spectrum: retroreflective, polarized retroreflective (ideal for shiny targets), standard diffuse, fixed or adjustable background suppression, and transmitted beam (emitter + receiver pair). 42CM additionally offers Class 1 laser-diffuse and laser polarized-retro variants for small- object and long-range detection.
What does the -D4 vs -A2 suffix mean on a 42C catalog number?
-D4 is a 4-pin M12 DC micro quick-disconnect pigtail — the standard and preferred termination. -A2 is a 2 m integral PVC cable without a connector. Replace -D4 with -A2 at the tail of the catalog number to switch styles (for example, 42CA-P2MPA-D4 becomes 42CA-P2MPA-A2).
Is the Bulletin 42CS stainless steel sensor safe for food-and-beverage wash-down?
Yes. The 42CS is 316L stainless steel with laser-etched markings (no stickers to peel off), rated IP67 and IP69K, and carries ECOLAB and Johnson Diversey approvals for high-pressure high-temperature sanitary wash-down. Its extended operating temperature range is -25…+85 °C.
What cordset and reflector do I order with a 42C sensor?
The recommended cordset is 889D-F4AC-2 (straight 4-pin M12 DC micro, 2 m). Right-angle cordsets are also available as 889D-R4AC-2. For retroreflective models, Rockwell recommends reflector 92-47 (32 mm / 1.25 in. diameter) or 92-39 (76 mm / 3 in.) — the larger reflector improves margin on longer retroreflective ranges.
Are 42C sensors IO-Link enabled?
No. The Bulletin 42C family (per Publication 42C-TD001A-EN-P, October 2018) uses discrete NPN or PNP outputs with optional light/dark-operate selection. For IO-Link-enabled photoelectric sensors, Rockwell's current-generation families (e.g., 42EF / 45 Series) should be consulted instead.

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