Product Overview

The Siemens 6ES7132-6HC70-0BU0 is a relay-based digital output module for the SIMATIC ET 200SP distributed I/O system. Its official product designation is RQ 3x120VDC-230VAC/5A CO n.i. ST, identifying a three-channel relay output module with non-isolated changeover contacts.

The module is used to switch external electrical loads through relay contacts controlled by a SIMATIC automation system. Each channel provides one normally open and one normally closed contact, allowing different external circuit configurations.

The 6ES7132-6HC70-0BU0 supports switching voltages from 24 to 120 V DC and 24 to 230 V AC. It has a maximum switching current of 5 A per channel for resistive loads and 2 A for inductive loads.

Unlike the 6ES7132-6HC50-0BU0, this version uses non-isolated relay contacts between channels. The contacts are electrically separated from the backplane bus and electronics supply, but the three output channels share a common electrical reference. This distinction is important when designing external load circuits.

The module is installed on a compatible ET 200SP BU type U0 BaseUnit and communicates with the controller through the station backplane bus. It supports STEP 7 V16 or higher with the appropriate Hardware Support Package, as well as GSD-based configuration.

Typical applications include switching solenoid valves, DC contactors, indicator lights, and auxiliary control circuits in distributed industrial automation systems.

Technical Specifications

Product Features

• Three Relay Output Channels: Provides three independent digital switching outputs for external electrical loads.
• Changeover Contacts: Each output includes normally open and normally closed contacts for flexible circuit configuration.
• Non-Isolated Channel Design: The three relay output channels share a common electrical reference.
• Wide Switching Voltage Range: Supports 24–120 V DC and 24–230 V AC external switching circuits.
• 5 A Resistive Load Capacity: Supports a maximum resistive switching current of 5 A per channel.
• Inductive Load Capability: Supports inductive switching loads up to 2 A per channel.
• 24 V DC Supply: Uses a 24 V DC supply for the relay coils and module electronics.
• Module Diagnostics: Provides configurable diagnostic functions and supply voltage monitoring.
• Substitute Value Configuration: Supports configurable substitute values for individual output channels.
• ET 200SP Integration: Installs on a compatible BU type U0 BaseUnit within the distributed I/O station.

Product Working Principle

The Siemens 6ES7132-6HC70-0BU0 converts digital commands from the SIMATIC controller into relay switching operations.

When the controller sends an output command through the ET 200SP backplane bus, the module processes the corresponding channel command and energizes the associated relay coil using the 24 V DC supply.

The electromagnetic force changes the position of the relay contacts. Each channel uses a changeover arrangement, allowing the common terminal to connect to either the normally open or normally closed contact.

This switching action controls the external electrical circuit without requiring the PLC output electronics to carry the external load current directly.

A simplified control arrangement is:

SIMATIC PLC → ET 200SP Interface Module → Backplane Bus → 6ES7132-6HC70-0BU0 → Relay Contacts → External Loads

The three relay channels share a common electrical reference. Consequently, the external wiring must account for the non-isolated channel arrangement when different voltage sources or circuit potentials are involved.

The module supports resistive loads up to 5 A and inductive loads up to 2 A per channel. Since inductive loads can generate voltage transients when switched off, suitable external suppression should be considered.

The module also monitors its supply voltage and provides diagnostic information through its LED indicators. This allows maintenance personnel to identify module status and supply-related problems during commissioning and operation.

Role in Siemens SIMATIC ET 200SP Control Architecture

Within the SIMATIC ET 200SP architecture, the 6ES7132-6HC70-0BU0 functions as a distributed relay output module between the PLC control program and external electrical equipment.

The controller executes the automation logic and transfers output commands through the ET 200SP interface module. These commands travel across the station backplane bus to the relay output module.

The module then changes the corresponding relay contacts to operate the connected field circuits.

A typical control arrangement is:

SIMATIC PLC → ET 200SP Interface Module → Backplane Bus → 6ES7132-6HC70-0BU0 → Field Devices

The non-isolated channel arrangement should be considered when designing the external switching circuits, particularly when multiple voltage sources are connected to the same module.

Industrial Applications

The 6ES7132-6HC70-0BU0 is suitable for distributed industrial control systems requiring relay-based switching of external electrical loads.

Installation and Maintenance

1. Verify the Module Number: Confirm that 6ES7132-6HC70-0BU0 matches the project hardware configuration and required output characteristics.
2. Check BaseUnit Compatibility: Use a compatible BU type U0 BaseUnit and verify the mechanical coding arrangement before installation.
3. Inspect the Module: Check the housing, connector contacts, and terminal interfaces for visible damage.
4. Isolate the Power Supply: Disconnect the relevant power supplies before installing or removing the module.
5. Mount the Module: Install the module on the designated ET 200SP BaseUnit and ensure that it is securely seated.
6. Verify Supply Voltage: Confirm that the 24 V DC supply is within the specified 19.2–28.8 V DC operating range.
7. Check Relay Output Wiring: Connect the common, normally open, and normally closed terminals according to the Siemens wiring diagram.
8. Consider Channel Commonality: Account for the non-isolated output arrangement when connecting external circuits with different voltage sources.
9. Verify Load Ratings: Ensure that resistive loads do not exceed 5 A and inductive loads do not exceed 2 A per channel.
10. Install External Protection: Provide the specified fast-acting fuse protection for the relay output circuits, following Siemens installation requirements.
11. Configure the Module: Configure the module in STEP 7 V16 or higher with the appropriate HSP 0321, or use the applicable GSD configuration.
12. Perform Functional Testing: Test all three relay channels, verify contact switching, inspect LED indications, and document the commissioning results.

During maintenance, inspect the terminal connections, external protection devices, and relay switching performance. Pay particular attention to inductive loads and switching frequency because these factors influence relay contact service life.

Compatible System Components

Recommended Related Models

Key Advantages

• Three relay output channels with changeover contacts.
• Supports AC and DC external switching circuits.
• Maximum 5 A resistive switching current per channel.
• Supports inductive loads up to 2 A per channel.
• Non-isolated channel configuration for shared-reference circuits.
• Supply voltage and module diagnostics.
• Compatible with ET 200SP distributed I/O architecture.
• Configurable through STEP 7 V16 or higher with the appropriate hardware support.

Technical FAQs

1. What does the n.i. designation mean in 6ES7132-6HC70-0BU0?

The n.i. designation means non-isolated. The three relay output channels do not have electrical isolation from one another and share a common electrical reference. However, they remain electrically separated from the backplane bus and electronics supply.

2. What is the difference between 6ES7132-6HC70-0BU0 and 6ES7132-6HC50-0BU0?

Both modules provide three relay outputs with changeover contacts and support the same general switching voltage ranges. The main difference is the channel isolation arrangement: the 6HC70 uses non-isolated output channels, while the 6HC50 provides isolated channels.

3. Can the 6ES7132-6HC70-0BU0 control solenoid valves?

Yes. Siemens identifies solenoid valves as a suitable application. However, the inductive load current must remain within the specified 2 A limit per channel, and appropriate external suppression should be considered.

4. Which engineering software is required for the 6ES7132-6HC70-0BU0?

The module supports STEP 7 V16 or higher with Hardware Support Package HSP 0321. It can also be configured through the corresponding GSD file in compatible automation engineering environments.