M12 and M8 circular sensor connectors: thread, coding A / B / D / X, pin counts and panel-mount hole sizes (+ hole gauge) — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/m12-m8-circular-sensor-connectors/ (sheet CC BY 4.0) Basis: HARTING coding table (IEC 61076-2-101 / -104 / -109 / -111 / -113 / -114), Pepperl+Fuchs mounting-hole table from two data sheets, M8Con / IO Connections / CUI sheets for threads; hole gauge file is Xem-drawn Catalog version: 2026-10-20 Sizes: see table below - M12 and M8 are the round sensor / actuator connectors on industrial machines. The coupling thread is M12 × 1 (IEC 61076-2-101; Pepperl+Fuchs) or M8 × 1 (IEC 61076-2-104; the M8Con sheet read). The coding is the key pattern that stops mismatched plugs; it is not the pin count, though each coding has typical counts. The coding table is HARTING's (standards and applications) with pin counts as it states them; L-com's overview lists the same letters (A sensors and DC power, B PROFIBUS, D 100 Mbit Ethernet, K and S AC power, L DC power, X 10 Gigabit Ethernet) without standard numbers or pin counts. - Panel mounting is a different thread from the coupling thread. The panel-mount (receptacle) body threads read are M16 × 1.5 or PG9 for M12 receptacles (Pepperl+Fuchs; IO Connections lists 'PG9 or M16×1.5'; a CUI D-coded sheet gives M16 × 1.5), M8 × 0.5 for M8, and PG13.5 for larger bodies. Pepperl+Fuchs prints one mounting-hole table on two data sheets (V1-PG9-500 and V1-PG13,5-Y124355): hole Ø M8 × 0.5 8.2, M12 × 1 12.2, M16 × 1.5 16.1, M20 × 1.5 20.1, PG9 15.3, PG13.5 20.5 mm (hole tolerances +0.1 to +0.2 printed; 1 × 45° chamfer). That V1-PG9-500 receptacle tightens at 3 to 4 Nm (locknut not included). The column labels in the extracted text are positional (hole Ø is column B), so confirm on the maker's drawing for your connector. - Not in any text read: the wrench size, panel thickness range and the front / rear flange diameter of each connector; the IO Connections and Pepperl+Fuchs drawings carry those as unlabelled picture callouts. M8 mounting-hole values for M8 × 1 receptacles were also not readable (Mouser's M8Con sheet references a drawing only). - File: a panel-hole gauge plate with the six Pepperl+Fuchs hole diameters (8.2, 12.2, 15.3, 16.1, 20.1, 20.5) to test-fit a receptacle thread before drilling a panel. Plate size, spacing and thickness are an example; the holes are the maker's. - Related: the cable-gland page has the M12 to M63 metric thread panel holes (EN 60423); the panel-cutouts page has other connector cut-outs. coding / feature thread standard poles use panel hole Ø, mm source note A-coded M8 M8 × 1 coupling thread IEC 61076-2-104 3 to 12 (HARTING; the A-coded M8 sheet read: 3 and 4 pin) sensor and actuator signals, field-device power A-coded M12 M12 × 1 coupling thread IEC 61076-2-101 3 to 12 (4, 5 and 8 on the receptacle pages read) sensor and actuator signals, field-device power B-coded M12 M12 × 1 coupling thread IEC 61076-2-101 2, 4 or 5 PROFIBUS fieldbus D-coded M8 M8 × 1 coupling thread IEC 61076-2-114 not stated industrial Ethernet up to 100 Mbit/s D-coded M12 M12 × 1 coupling thread IEC 61076-2-101 4 (a D-coded receptacle read: 4 positions, pin Ø1 mm) industrial Ethernet up to 100 Mbit/s K-coded M12 M12 × 1 coupling thread IEC 61076-2-111 4 + PE power for small drives L-coded M12 M12 × 1 coupling thread IEC 61076-2-111 4 + FE device power at high current and voltage P-coded M8 M8 × 1 coupling thread IEC 61076-2-114 4 EtherCAT P data and power S-coded M12 M12 × 1 coupling thread IEC 61076-2-111 3 + PE power for smaller devices X-coded M12 M12 × 1 coupling thread IEC 61076-2-109 8 industrial Ethernet up to 10 Gbit/s Y-coded M12 M12 × 1 coupling thread IEC 61076-2-113 8 hybrid signal and power mounting hole for a receptacle with M8 × 0.5 body thread 8.2 Pepperl+Fuchs mounting drawing (hole Ø 'B') mounting hole for a receptacle with M12 × 1 body thread 12.2 Pepperl+Fuchs mounting drawing (hole Ø 'B') mounting hole for a receptacle with PG9 body thread 15.3 Pepperl+Fuchs mounting drawing (hole Ø 'B') mounting hole for a receptacle with M16 × 1.5 body thread 16.1 Pepperl+Fuchs mounting drawing (hole Ø 'B') mounting hole for a receptacle with M20 × 1.5 body thread 20.1 Pepperl+Fuchs mounting drawing (hole Ø 'B') mounting hole for a receptacle with PG13.5 body thread 20.5 Pepperl+Fuchs mounting drawing (hole Ø 'B') Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - HARTING: Circular coding: M8 / M12 codings A, B, D, K, L, P, S, X, Y with IEC 61076-2-xxx numbers, pole counts and applications — web — Publisher's page; dimensions are facts — https://www.harting.com/en-NL/circular-coding - Pepperl+Fuchs: V1-PG9-500 M12 / PG9 4-pin receptacle: plug thread M12 x 1 per IEC 61076-2-101, torque 3 to 4 Nm, mounting hole table by thread — web — Publisher's page; dimensions are facts — https://files.pepperl-fuchs.com/webcat/navi/productInfo/pds/456934_eng.pdf - Pepperl+Fuchs: V1-PG13,5-Y124355 M12 / PG13.5 receptacle: same mounting hole table, locknut included — web — Publisher's page; dimensions are facts — https://files.pepperl-fuchs.com/webcat/navi/productInfo/pds/124355_eng.pdf - Pepperl+Fuchs: M12 x 1 A-coded receptacles with M16 or PG9 mounting thread, 4 / 5 / 8 pins — web — Publisher's page; dimensions are facts — https://files.pepperl-fuchs.com/online-catalogs/911360/files/assets/basic-html/page1040.html - Mouser (M8Con datasheet): M8 straight panel-mount connectors 3 / 4 pin, A-coded, M8 x 1, IEC 61076-2-104, 4 A / 60 V — web — Publisher's page; dimensions are facts — https://www.mouser.com/datasheet/2/743/M8Con_3_4_M_SC_F_v1_0-3500914.pdf - IO Connections (elitaliaweb copy): M12 male panel mount front-fastened: codings A, B, C, D; 3 to 17 pins; chassis thread 'PG9 or M16 x 1.5' — web — Publisher's page; dimensions are facts — https://elitaliaweb.it/images/uploads/ds-ioconnections/M12_MB12MBxFFxxST-X.pdf - Same Sky (CUI Devices): CDM1211-04D-MT-F9-67: M12 D-coded 4-position receptacle, M16 x 1.5 mounting thread, IP67 — web — Publisher's page; dimensions are facts — https://www.sameskydevices.com/product/interconnect/connectors/circular-connectors/cdm1211-04d-mt-f9-67 - L-com: M12 connector coding demystified (A to X by application) — web — Publisher's page; dimensions are facts — https://www.l-com.com/resources/blog/m12-connector-coding-demystified Free files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/m12-m8-circular-sensor-connectors/index.json API: https://xemstudio.com/api/geometry?object=m12-m8-circular-sensor-connectors