Product Overview
The Siemens 405-4DAC-2, with the full order number 6ES7 405-4DA02-0AA0, is a high-density, 16-channel analog output module designed for the robust SIMATIC S7-400 programmable logic controller system. This module serves as a critical interface between the digital control world of the PLC and the analog actuation elements in the field, converting precise digital setpoint values generated by the control program into standardized analog current signals, primarily the industry-standard 4-20mA. The Siemens 405-4DAC-2 is engineered for applications requiring the simultaneous control of multiple final control elements, such as control valves, proportional hydraulic valves, variable speed drive speed references, or electrical actuator positioners, making it indispensable in complex process and manufacturing automation systems. Its high channel count provides exceptional I/O density, optimizing space within the S7-400 rack and reducing the number of modules required for large-scale projects.As a member of the high-performance S7-400 I/O family, the 405-4DAC-2 module is characterized by its precision, reliability, and advanced diagnostic capabilities. It operates under the centralized I/O architecture of the S7-400, meaning it is installed directly in the central controller rack, benefiting from the high-speed backplane communication with the CPU. Each of its 16 channels is independently configurable, allowing engineers to tailor parameters like output type (4-20mA being typical), diagnostics, and behavior on channel faults. The module incorporates sophisticated technology to ensure signal integrity, including galvanic isolation between the backplane logic, the module’s internal electronics, and the field-side outputs. This isolation protects the sensitive central controller from disturbances and potential overvoltages originating in the field wiring. The value of the Siemens SIMATIC 405-4DAC-2 lies in its ability to deliver a large number of precise, stable, and reliable control outputs from a single module slot, supporting the creation of sophisticated, data-intensive control strategies in industries ranging from chemical processing to automotive manufacturing, all within Siemens’ premier high-availability PLC platform.
Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | 405-4DAC-2 (Full order number: 6ES7 405-4DA02-0AA0) |
| Manufacturer | Siemens AG |
| Product System | SIMATIC S7-400 |
| Product Type | Analog Output Module |
| Number of Channels | 16 |
| Output Signal Type | Current output, typically 4-20mA; 0-20mA configurable |
| Output Resolution | 15 bits (including sign) for high precision |
| Load Impedance | Typically 0 to 500 Ohms for 4-20mA operation |
| Accuracy (at 25°C/77°F) | High accuracy, typically < ±0.1% of full-scale value |
| Cycle Time (update of all channels) | Short, configurable (e.g., in the range of 10-100ms per channel group) |
| Electrical Isolation | Yes, between backplane, channels, and field |
| Diagnostics | Extensive: Wire-break (open circuit), short-circuit to ground, underflow/overflow |
| Connection | Via front connector (40-pin) |
| Power Loss Behavior | Configurable per channel (e.g., hold last value, output substitute value) |
| Operating Temperature | 0 to 60 °C |
| Dimensions | Standard S7-400 module format |
Main Features and Advantages
The Siemens 405-4DAC-2 analog output module offers a powerful set of features designed for precision, reliability, and ease of engineering in demanding control environments. Its foremost advantage is the high channel density—16 independently controlled analog outputs in a single module slot—which maximizes the I/O capacity of an S7-400 rack and simplifies cabinet layout, reducing hardware footprint and overall system cost. Each channel provides high-resolution 15-bit conversion, ensuring fine control over field devices and enabling precise positioning and modulation. The module supports a wide range of configurable parameters through Siemens STEP 7 engineering software, allowing each channel to be individually tailored for its specific task. Engineers can define the output type (e.g., 4-20mA), enable/disable diagnostics, and set precise behavior in case of a fault (such as outputting a defined substitute value or holding the last value), which is critical for process safety and stability.Advanced diagnostic capabilities are integral to the Siemens 405-4DAC-2‘s value proposition. The module can continuously monitor each output channel for critical faults such as wire-break (open circuit, where the loop resistance is too high) and short-circuit to ground. It can also detect underrange and overrange conditions. These diagnostics are reported directly to the CPU and can be used to trigger immediate alarms or predefined safe reactions within the control program, enabling predictive maintenance and rapid fault localization. The module’s galvanic isolation protects the central controller’s backplane from electrical noise and potential hazards present in the field, enhancing overall system robustness. Furthermore, the cyclic self-calibration feature helps maintain long-term accuracy by compensating for temperature drift and component aging. The combination of high density, precision, robust diagnostics, and flexible configuration makes the Siemens SIMATIC 405-4DAC-2 an exceptionally reliable and efficient solution for driving a multitude of analog final control elements in mission-critical automation systems.
