6ES7972-0BB12-0XA0 Siemens Bus Connector

Modelo completo & Official Description

Nro. de orden: 6ES7 972-0BB12-0XA0

SIMATIC DP, PROFIBUS Bus Connector, arriba a 12 Mbit/s; 90° vertical cable outlet, with PG programming socket, integrated switchable isolated termination resistor, screw terminal wiring.

Desglose del código del modelo

Segmento de código	Definición
6ES7	SIMATIC S7 automation system accessories
972	PROFIBUS RS485 bus connector series
0CAMA Y DESAYUNO	90° outlet + with PG programming socket; 0BA = without PG socket
12	Terminal de tornillo (non-FastConnect stripping structure)
0XA0	Standard general version (Hecho en Alemania)

Núcleo Eléctrico & Especificaciones mecánicas
Communication Standard: PROFIBUS-DP / IPM (RS485)
Max Baud Rate: 12 Mbit/s
Termination Resistor: Built-in 220Ω, ON/OFF toggle switch (con aislamiento)

Termination switch set to ON for the first and last station on the bus; OFF for all intermediate stations

Método de cableado: Terminales de tornillo, conventional cable stripping, FastConnect cable is NOT supported
Interfaces: Rear 9-pin Sub-D male connector; independent front 9-pin PG female socket (online debugging without bus interruption)
Salida de cables: 90° vertical downward outlet, suitable for compact cabinet installation
Dimensiones generales: 15.8 milímetros(W.) × 64 milímetros(h) × 35.6 milímetros(D)
Clase de protección: IP20 (indoor cabinet installation only)
Rango de temperatura: Operante: 0 ℃ ~ +60 ℃; Almacenamiento: -40 ℃ ~ +70 ℃
Peso neto: Aprox.. 60 gramo
Wiring Definition (Standard PROFIBUS Purple Cable)

Terminal A: Green signal wire

Terminal B: Red signal wire

> ⚠️ Reversing A/B will directly trigger communication failure; secure the cable shield to the connector metal clamp with grounding at both cable ends.

Cross Comparison of Similar Models (Referencia de selección)

Número de orden	Outlet Angle	PG Socket	Tipo de cableado
6ES7972-0BB12-0XA0	90°	✅ Yes	Terminal de tornillo (este modelo)
6ES7972-0BA12-0XA0	90°	❌ No	Terminal de tornillo
6ES7972-0BB42-0XA0	35° angled outlet	✅ Yes	Terminal de tornillo
6ES7972-0BB52-0XA0	35° angled outlet	✅ Yes	FastConnect quick stripping

Applicable Devices & Escenarios

S7-300 / S7-400 CPU DP ports

ET200M, ET200S DP interface modules

PROFIBUS-DP inverters, servoaccionamientos, instrumentos, codificadores

S7-200 SMART RS485 (MPI/DP mode)

Notas clave de aplicación & Common Pitfalls
FastConnect quick stripping technology is not supported. FC cables cannot be directly crimped; select 0BB52 / 0BA52 series if FC cables are used.
Online monitoring via PG socket does not require bus disconnection, ideal for non-stop equipment debugging.
Only enable termination resistors at the two ends of one PROFIBUS bus. Multiple active termination resistors cause unstable communication and packet loss.
Avoid excessive tension on terminals during cable bending. Reliably crimp the shield; dual-end grounding is strongly recommended for long-distance communication.
Wide-Temperature Special Version (For Harsh Environments)

6AG1972-0BB12-2XA0 (SIPLUS Version)

Derived from 6ES7972-0BB12-0XA0 with anti-corrosion coating. Temperatura de funcionamiento: -25℃ ~ +70℃, applicable to outdoor, climatización, metallurgy and high-humidity environments.

Información de reemplazo

Direct form-fit replacement: Prioritize identical part number for no hardware modification.

If 35° angled outlet is required: Replace with 6ES7972-0BB42-0XA0.

Para nuevos proyectos, prefer FastConnect version 6ES7972-0BB52-0XA0 for higher wiring efficiency.

Supplementary Document: PROFIBUS DP Topology, Especificación de cableado & Matriz de solución de problemas

Compatible with 6ES7972-0BB12-0XA0 Bus Connector

Standard PROFIBUS Bus Topology (Linear Topology; Star/Tree Topology Forbidden)

Mandatory Topology Rules

Linear daisy-chain connection only; T-branches and star wiring are strictly prohibited. Branches cause signal reflection, communication jitter and packet loss.
Set termination resistor to ON only on the first and last connectors of the whole bus; all intermediate stations must be set to OFF.
Maximum two cables (EN / AFUERA) per bus connector. Do not terminate multiple wires on one screw terminal.
Detailed Wiring Specification for 6ES7972-0BB12-0XA0

2.1 Definición de terminal

A: Green wire

B: Red wire

> ⚠️ Red = B, Green = A. A and B must not be swapped.

2.2 Shield Handling

Unfold the metal shielding braid of PROFIBUS purple cable; do not cut off the copper mesh.
Lay shielding braid flat and clamp under the metal shield clip of the connector.
Cabinet layout recommendation: Reliably ground the shield at both ends of the bus. Dual-end grounding is preferred for long-distance and high-interference sites; single-end grounding is adopted if potential difference exists between ground points.
Never short shielding braid with signal wires A/B!

2.3 Termination Resistor Switch Operation

EN: 220Ω termination resistor activated (for first & last station)

APAGADO: Termination resistor disconnected (all intermediate stations)

> Typical Fault: Multiple stations with termination resistor ON → Impedance mismatch, frequent communication errors.

2.4 PG Programming Socket Instructions

This model integrates a 9-pin female PG socket:

Programming cable can be plugged for online monitoring without cutting off the bus.

⚠️ PG socket is only for temporary debugging; do not permanently connect other slave devices.

Step-by-Step Wiring Procedure
Unscrew and open the connector housing;
Strip outer cable sheath, remove 6~7mm insulation of red/green cores;
Route red wire to terminal B, green wire to terminal A. Tighten screws with torque 0.4~0.6Nm (avoid thread slipping);
Clamp shielding braid into metal shield clip;
Verify no short circuit between A and B, no exposed conductors touching each other;
Toggle termination resistor switch according to station position;
Close housing, insert connector into module Sub-D port and lock fixing screws.
PROFIBUS DP Communication Troubleshooting Matrix

Síntoma de falla	Causa principal	Stepwise Remedial Actions
All stations offline; master reports DP fault (BF LED steady red)	1. Termination resistors disabled at both ends	1. Check two end connectors, set termination switch to ON
	2. A/B reversed for the whole bus	2. Verify A(verde)/B(rojo) wiring section by section
	3. A/B short-circuit somewhere on bus	3. Apagar, use multimeter to check A-B short circuit
	4. Broken bus cable	4. Isolate cable segments to locate break point
Random drop-out of partial slaves, flashing BF LED, intermittent communication	1. Termination resistor mistakenly enabled on intermediate stations	1. Inspect termination switch on every connector
	2. Mala conexión a tierra del blindaje & interferencia electromagnética	2. Re-tighten shield crimp and grounding bar
	3. Cracked/bent cable insulation	3. Rewire to eliminate all branch lines
	4. Branched (star) bus wiring	4. Cross-check baud rate vs maximum cable length table
	5. Baud rate too high, bus length exceeds limit
Devices near master run normally, remote slaves drop out frequently	1. Bus length exceeds limit corresponding to selected baud rate	1. Reduce communication baud rate
	2. Ground loop interference caused by multi-point grounding	2. Optimize shield grounding scheme
	3. Low-quality non-standard PROFIBUS Type A cable	3. Replace with certified PROFIBUS Type A cable
Communication fails after PG cable insertion; restored after unplugging	PG cable contains built-in termination resistor, conflicting resistance at bus terminal	Avoid long-term PG connection on end-node connectors; use PG socket on intermediate stations for debugging
Communication works after commissioning, failure occurs after equipment vibration	Loose screw terminals, mal contacto del cable; cable tension pulling connector	Retighten terminal screws; fix cables with cable ties to avoid mechanical load on connectors

Baud Rate — Maximum Cable Length Table (PROFIBUS Type A Cable)

Velocidad de baudios	Max Bus Length
9.6 kbit/s	1200 metro
19.2 kbit/s	1000 metro
187.5 kbit/s	400 metro
500 kbit/s	200 metro
1.5 Mbit/s	100 metro
3 ~ 12 Mbit/s	100 metro

Strict Forbidden Operations (Red Line Rules)
❌ Do not terminate more than two signal wires under one screw terminal
❌ Do not construct PROFIBUS bus with star topology or T-branches
❌ Do not activate termination resistor on multiple stations simultaneously
❌ Do not swap signal wire A and B
❌ Do not short shielding braid with A/B conductors
❌ Do not replace standard PROFIBUS Type A cable with ordinary 2-core cable
❌ Do not sharply bend cable near the connector outlet to prevent internal wire fracture
Additional Selection Reminder

6ES7972-0BB12-0XA0 adopts screw terminal wiring and does NOT support FastConnect cables.

For new mass rollout projects, it is recommended to select:

6ES7972-0BB52-0XA0 (35° outlet + PG socket + FastConnect)