Product Overview

The Schneider TM3AQ4G is a four-channel analog output module in the Modicon TM3 expansion I/O family. It enables compatible Modicon PLC controllers to generate voltage and current reference signals for external equipment, extending the controller’s ability to regulate devices that require continuously variable commands rather than simple digital switching.

The module provides four independently configurable analog output channels. Supported signal ranges include 0–10 V, -10–10 V, 0–20 mA, and 4–20 mA. These are commonly used for variable speed drive references, proportional valve positioning, process control equipment, and other industrial devices with analog command inputs.

In a water pumping system with several independently controlled pumps, the TM3AQ4G can generate separate speed references for multiple variable frequency drives. The PLC calculates the required operating values from process conditions and sends the corresponding analog commands through the module. Each drive then adjusts its motor operation according to its configured input range.

The four-channel arrangement is also useful in production machinery where several actuators need independent control. For example, a machine may use separate analog outputs for conveyor speed, material feed rate, valve position, and another process reference. These commands can be managed through one expansion module rather than allocating separate modules for each output.

A distinguishing feature of the TM3AQ4G is its removable spring terminal block with a 5.08 mm pitch. This connection method allows conductors to be secured without conventional screw tightening and makes the module suitable for control cabinets using spring-clamp wiring practices.

The TM3AQ4G belongs to the same four-output module group as the TM3AQ4. The main hardware distinction is the terminal arrangement: TM3AQ4G uses spring terminals, while TM3AQ4 uses screw terminals. This difference should be checked when replacing an existing module or standardizing the wiring arrangement of a control cabinet.

Technical Specifications

Product Features

• Four independent analog output channels in one expansion module.
• Supports both voltage and current output signals.
• Configurable 0–10 V and -10–10 V voltage ranges.
• Supports 0–20 mA and 4–20 mA current ranges.
• 12-bit resolution or 11 bits plus sign, depending on the selected output range.
• Removable spring terminal blocks for field connections.
• 24 V DC rated supply voltage.
• 1 ms output stabilisation time.
• Supports resistive output loads.
• Short-circuit and open-circuit output protection.
• Compatible with Modicon M221, M241, M251, and M262 controllers.
• Uses the Modicon TM3 expansion bus.
• Supports twisted shielded-pair output cables up to 30 m.
• Green PWR LED for local power status indication.
• DIN rail and panel mounting options.
• IP20 protection for installation inside industrial control enclosures.

Working Principle

The TM3AQ4G converts digital commands generated by the PLC into analog electrical signals. These signals are then used by external equipment as references for speed, position, flow, or other continuously adjustable operating values.

A typical signal path is:

PLC Control Program → TM3 Expansion Bus → TM3AQ4G → Analog Output Signals → Drives / Actuators

The PLC application determines the required output values according to machine conditions, operator commands, or process feedback. The TM3AQ4G receives these digital values through the TM3 expansion bus and converts them into the selected voltage or current signals.

For example, consider a production line with four variable speed drives. Each drive receives an independent 0–10 V reference from one of the TM3AQ4G output channels. The PLC can adjust the four references separately to coordinate conveyor speeds, regulate material feeding, and maintain the required production sequence.

Current-loop control follows the same principle. A 4–20 mA output can be connected to a compatible proportional valve or process controller. The receiving device interprets the current according to its configured operating range and adjusts its output accordingly.

Each output channel can be configured individually through EcoStruxure Machine Expert. This allows the module to accommodate different signal requirements within the same installation, such as voltage-controlled drives on some channels and current-controlled actuators on others.

The output load must match the selected signal type. Voltage outputs require a load impedance of at least 1 kΩ, while current outputs support a maximum load impedance of 300 Ω. These limits should be checked before connecting external equipment.

The conversion time is related to the number of channels being processed and the controller cycle time. In applications involving four frequently updated output references, this timing should be considered when determining how quickly the connected equipment needs to respond to changes in the PLC program.

Role in a Modicon TM3 PLC Control Architecture

The TM3AQ4G acts as the analog command interface between a Modicon PLC and external control devices. While digital output modules handle discrete commands, this module generates continuously variable reference signals that allow the PLC to regulate equipment operating values.

A typical control arrangement is:

Modicon PLC → TM3 Expansion Bus → TM3AQ4G → Analog Reference Signals → Drives / Proportional Actuators

In a multi-pump control system, the PLC can calculate individual speed references according to pressure demand and operating conditions. The TM3AQ4G sends these commands to the connected drives through its four output channels.

In a different application, the channels may be assigned to separate proportional actuators. The controller can then adjust several process variables independently without requiring a separate analog output module for every controlled device.

The module is particularly useful in systems where the number of analog command points has increased beyond the controller’s built-in output capacity.

Industrial Applications

Installation and Maintenance

1. Verify the Module Reference: Confirm that the required module is TM3AQ4G. The TM3AQ4 uses screw terminals, whereas the TM3AQ4G uses spring terminal connections.
2. Check Controller Compatibility: Verify that the installed Modicon M221, M241, M251, or M262 controller supports the planned TM3 expansion configuration.
3. Identify Connected Equipment: Determine which external devices will receive the four analog output signals and record their respective control requirements.
4. Confirm Output Signal Types: Check whether each receiving device requires 0–10 V, -10–10 V, 0–20 mA, or 4–20 mA operation.
5. Verify the Power Supply: Ensure that the external supply remains within the specified 20.4–28.8 V DC range.
6. Inspect Spring Terminals: Check that conductors are correctly inserted and securely held by the removable spring terminal blocks.
7. Use Suitable Signal Cables: Use twisted shielded-pair cables for analog output circuits and keep cable length within the specified 30 m limit.
8. Check Output Load Impedance: Confirm that voltage output loads are at least 1 kΩ and current output loads do not exceed 300 Ω.
9. Configure Individual Channels: Set the correct output mode for each channel in EcoStruxure Machine Expert and verify that the software settings match the physical wiring.
10. Measure Output Signals: Check the actual voltage or current at the terminals and compare the measurements with the values commanded by the PLC.
11. Inspect Abnormal Output Conditions: If an external device does not respond correctly, examine the output wiring, load impedance, channel configuration, and external power supply.
12. Document Channel Assignments: Record the connected equipment, selected signal ranges, and PLC output addresses to simplify future troubleshooting and module replacement.

Related Components

Recommended Related Models

Key Advantages

• Four analog output channels for controlling multiple external devices.
• Supports standard industrial voltage and current reference signals.
• Individual channel configuration accommodates different control requirements.
• 12-bit resolution or 11 bits plus sign, depending on the selected range.
• Spring terminal connections simplify field wiring.
• Compatible with four Modicon PLC controller families.
• Short output stabilisation time supports changing control references.
• Suitable for variable speed drives and proportional actuators.
• Combines four analog command points within one compact expansion module.

Technical FAQs

Can the TM3AQ4G control four different devices independently?

Yes. The module has four independently configurable analog output channels. Each channel can generate its own voltage or current reference, allowing the PLC to control four compatible devices separately. The receiving equipment must support the selected signal type and range.

What is the difference between TM3AQ4G and TM3AQ4?

Both modules provide four analog output channels and support the same general voltage and current ranges. The main difference is the terminal connection method. TM3AQ4G uses removable spring terminal blocks, while TM3AQ4 uses removable screw terminal blocks. The correct version should be selected according to the existing cabinet wiring arrangement.

Can the TM3AQ4G provide 4–20 mA signals to proportional control valves?

Yes. One or more output channels can be configured for 4–20 mA operation when the connected proportional valves support this input standard. The PLC program determines the required current reference, and the module converts the digital command into the corresponding analog output. The receiving device’s input impedance must remain within the module’s specified current-output load limit.

What should be checked if one of the four analog outputs stops responding?

Start by checking the channel configuration and the physical wiring. Confirm that the selected voltage or current mode matches the receiving device and that the output load is within the specified impedance range. Also inspect the external 24 V DC supply, terminal connections, and PLC output values. If the other channels operate normally, checking the affected channel’s configuration and wiring separately can help isolate the problem.