How to Read an Accent Part Number: The Complete Ordering Code Guide

Every Accent sensor part number describes the complete specification of the product. Series, body size, sensing distance, output type, contact function, wiring and protection are all in there. Once the pattern is clear, you can read any part number off a label and write a replacement code without opening a catalogue.

This page is the decoder for the whole range.

The series prefix

The first four characters identify the technology:

• D30C — DC inductive proximity switch, three-wire. The general-purpose range.
• D31C — photoelectric switch.
• D32C — capacitive proximity switch.
• D33C — magnetic proximity switch, including speed and direction variants.
• D20C — NAMUR inductive proximity switch, for intrinsically safe duty.
• A20C — AC two-wire inductive proximity switch.

Inductive, capacitive and NAMUR: D30C, D32C, D20C, A20C

These follow a common pattern:

D30C-1204-NM-3S

D30C	Series
12	Body thread in mm — 08, 12, 18, 30, 36 or 50
04	Nominal sensing distance in mm
N	Output transistor — N for NPN, P for PNP
M	Contact function — M for normally open (make), B for normally closed (break)
3S	Three-wire, short-circuit protected. Plain 3 omits the protection.

So the body and sensing distance pair together as four digits. 1204 is M12 with 4 mm sensing. 5030 is M50 with 30 mm. 3015 is M30 with 15 mm.

A20C differs only in the output section, because an AC two-wire sensor has no transistor type. A20C-1808-M-2 is M18, 8 mm, normally open, two-wire.

D20C NAMUR parts carry the NA suffix instead of an output code, because a NAMUR sensor does not switch a load — it changes the current it draws. D20C-1805-NA is M18 with 5 mm sensing, NAMUR output.

Photoelectric: D31C

Photoelectric parts need two extra fields, because sensing mode and range are independent of body size.

D31C-18TB-15000-PL-2S

D31C	Series
18	Body thread — 18 or 30
TB	Sensing mode — TB through-beam, RR retro-reflective, DR diffuse reflective
15000	Sensing range in mm
P	Output — P for PNP, N for NPN
L	Logic — L for light-on, D for dark-on
2S	Short-circuit protected

Magnetic and speed sensing: D33C

D33C-18MD-NM-3S is an M18 magnetic proximity switch, NPN normally open, three-wire, short-circuit protected, rated 30 mA.

An additional SD suffix indicates the speed and direction variant, used for rotation monitoring where the control system needs to know not just that a shaft is turning but which way. D33C-30MD-NM-3S-SD is the M30 version.

Note the output current: the D33C range is rated 30 mA rather than the 200 to 300 mA of the switching ranges. It is designed to feed a controller input, not to drive a contactor directly. Driving a relay coil from one is a common and avoidable mistake.

Output current by series

• D30C — 200 mA and 300 mA depending on variant
• D31C — 200 mA
• D32C — 300 mA
• D33C — 30 mA
• A20C — 200 mA

Check the actual current your load draws. A contactor coil inrush can be several times its holding current, and a sensor sized on the holding figure will fail.

The suffixes that matter most

S for short-circuit protection. The difference between -3 and -3S. Small price difference, prevents the most common field failure. Specify it unless there is a reason not to.

M and B. Make and break — normally open and normally closed. Worth choosing deliberately rather than defaulting: on a safety-relevant interlock, normally closed means a cut cable produces the stopped state.

N and P. NPN and PNP. Determined by your input card, not preference. See PNP versus NPN sensors.

Reading a worn label

If the label on an installed sensor is partly illegible, you can usually reconstruct the code. Measure the thread to get the body size. Count the wires: two means A20C or D20C, three means one of the DC ranges. Trace the output to see whether it sources or sinks. Then send us what you have — a photograph of the sensor in place and its wiring is generally enough for us to identify the part.

Cross-referencing another manufacturer

If you are replacing a competitor part rather than an Accent one, send us the full part number from the label and the application. We will identify the equivalent rather than ask you to work through the decoder — see our guide to replacing imported proximity switches.