
( Brand: Allen Bradley ), ( Manufacturer Part Number: 1738-485ASCM12 ), ( Part Type: Module )
The **Allen-Bradley 1738-485ASC-M12** is a high-performance, modular **CompactLogix 1738** programmable logic controller (PLC) designed for industrial automation applications requiring robust, scalable, and reliable control solutions. Part of Rockwell Automation s **CompactLogix** series, this specific model features a **1738-485ASC** base unit paired with a **M12** communication module, offering enhanced connectivity and flexibility for modern manufacturing environments. The **1738-485ASC** base unit is a **12-slot chassis** that supports a variety of I/O modules, allowing engineers to configure the system precisely to match their automation needs whether for discrete manufacturing, process control, or machine-level automation. With a **1.5 GHz** dual-core processor and **1 GB** of RAM (expandable to **2 GB**), this PLC delivers high-speed processing and efficient execution of control logic, making it ideal for applications demanding real-time responsiveness, such as motion control, HMI integration, or complex sequencing operations.
The **M12** communication module integrated into this unit provides **EtherNet/IP** connectivity, enabling seamless integration with other Rockwell Automation devices, including **ControlLogix**, **CompactLogix**, **Studio 5000**, and **FactoryTalk View** systems. This module supports **full-duplex Ethernet communication** with a **10/100 Mbps** data transfer rate, ensuring reliable and high-speed data exchange for industrial networks. Additionally, the **M12** module includes **EtherNet/IP aliasing**, which simplifies device identification and reduces network configuration complexity, making it easier to implement distributed control architectures. The **1738-485ASC-M12** also supports **CIP (Common Industrial Protocol)** for advanced communication features, including **CIP Sync** for precise timing synchronization and **CIP Motion** for integrated motion control, further enhancing its suitability for applications requiring coordinated multi-axis motion.
Built to withstand the rigors of industrial environments, this PLC is housed in a **compact, rugged enclosure** that meets **NEMA 4X** and **IP65** standards, providing protection against dust, water, and harsh operating conditions. The **1738-485ASC** base unit includes **two integrated Ethernet ports**, one of which is occupied by the **M12** module, while the other can be used for additional networking or as a backup connection. The system also features **two serial ports (RS-232/422/485)** for legacy device integration, ensuring compatibility with older equipment while supporting modern communication protocols. With **128 MB** of onboard memory (expandable via optional **1738-MEM** modules), the **1738-485ASC-M12** provides ample storage for ladder logic programs, data tables, and configuration files, reducing the need for external memory devices.
Programming and configuration for this PLC are streamlined through **Rockwell Automation s Studio 5000 Logix Designer**, a powerful development environment that supports **ladder logic (LAD), structured text (ST), function block diagrams (FBD), and sequential function charts (SFC)**. The **EtherNet/IP** connectivity allows for easy remote programming, monitoring, and troubleshooting, while **FactoryTalk View** integration enables the creation of **human-machine interfaces (HMIs)** for operator interaction. The **1738-485ASC-M12** also supports **remote I/O** and **distributed control** architectures, enabling scalable solutions where I/O modules can be placed closer to the process for reduced wiring complexity and improved reliability. Additionally, its compatibility with **Rockwell s Safety Integration System (SIS)** allows for the integration of safety functions, ensuring compliance with **ISO 13849** and **IEC 61508** standards for safety-critical applications.
Overall, the **Allen-Bradley 1738-485ASC-M12** is a versatile, high-performance PLC designed for industrial automation professionals who require a **scalable, reliable, and future-proof** control solution. Whether deployed in **discrete manufacturing, process control, or motion-intensive applications**, this unit combines **powerful processing capabilities, robust networking, and seamless integration** with Rockwell s ecosystem of automation products. Its **compact yet expandable architecture**, **industrial-grade durability**, and **advanced communication features** make it an excellent choice for engineers seeking a **cost-effective yet high-performance** PLC for modern automation challenges.
### **Pros and Cons of buying a Allen-Bradley 1738-485ASC-M12 (CompactLogix 5370 Controller)**
#### **Overview**
The **Allen-Bradley 1738-485ASC-M12** is a **CompactLogix 5370 series PLC** with a **12-slot backplane**, **EtherNet/IP communication**, and **ASCII serial communication** capabilities. It is a mid-range controller designed for industrial automation applications requiring modular expansion, high-speed networking, and serial communication.
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### **Pros**
1. **Modular Expansion Capability**
- The **12-slot backplane** allows for flexible I/O expansion, accommodating a wide range of **Allen-Bradley and third-party modules** (digital, analog, high-speed, safety, etc.).
- Supports **1769-I/O modules**, enabling customization for specific automation needs.
2. **High-Speed Ethernet/IP Communication**
- Built-in **EtherNet/IP port** ensures fast, reliable industrial networking with **V10/V20 protocol support**, compatible with **Rockwell Automation s ControlLogix, CompactLogix, and other EtherNet/IP devices**.
- Enables **real-time data exchange** with HMIs, SCADA systems, and other PLCs.
3. **ASCII Serial Communication (ASC-M12 Module)**
- The **ASC-M12 module** provides **RS-232/RS-485 ASCII communication**, useful for interfacing with **legacy equipment, barcode scanners, printers, or non-Rockwell devices**.
- Supports **modbus RTU/ASCII** and other serial protocols via configuration.
4. **CompactLogix 5370 Platform Benefits**
- **Faster processing** compared to older CompactLogix models (e.g., 5370 vs. 5360).
- **Improved memory capacity** (up to **16MB user memory**), allowing for more complex programs.
- **Enhanced security features** (user roles, password protection, firmware updates).
- **Compatibility with Studio 5000** (Rockwell s latest engineering software).
5. **Reliability & Industrial Build**
- **Allen-Bradley is a trusted brand** with **long-term support** and availability of spare parts.
- **Wide operating temperature range** (-25 C to 60 C), making it suitable for harsh industrial environments.
- **High MTBF (Mean Time Between Failures)** due to robust hardware design.
6. **Backward & Forward Compatibility**
- Works with **older CompactLogix programs** (with minor adjustments).
- Supports **future Rockwell Automation software updates**.
7. **Cost-Effective for Mid-Range Applications**
- More affordable than **ControlLogix 5570/5580** but still offers **high performance**.
- **Lower total cost of ownership** compared to non-Rockwell PLCs requiring additional gateways for EtherNet/IP.
8. **Easy Integration with Rockwell Ecosystem**
- Seamless integration with **FactoryTalk View SE/ME, View Studio, and other Rockwell software**.
- Supports **remote I/O, distributed control, and cloud connectivity** via **FactoryTalk AssetCentre**.
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### **Cons**
1. **Limited Native High-Speed I/O**
- Unlike **ControlLogix**, the **CompactLogix 5370 does not have native high-speed I/O (HSI) slots** (e.g., for motion control or high-speed counting).
- Requires **additional modules (e.g., 1769-H1 or 1769-H2)** for advanced motion or high-speed applications.
2. **ASCII Module Requires Additional Licensing (If Needed)**
- The **ASC-M12 module** may require **additional licensing or firmware activation** depending on the application.
- Some **serial communication features** (e.g., advanced Modbus) may need **Studio 5000 Licensing**.
3. **Higher Power Consumption Than Smaller PLCs**
- Consumes more power than **microPLCs (e.g., 1769-L32E)** or **smaller CompactLogix models (e.g., 5370 with fewer slots)**.
- May require **dedicated power supplies** in some setups.
4. **Deprecated in Favor of Newer Models**
- Rockwell Automation has **phased out some CompactLogix 5370 models** in favor of **CompactLogix 5480/5580** (which offer **better performance, more slots, and USB connectivity**).
- **Long-term support may be reduced** compared to newer controllers.
5. **Potential Software Compatibility Issues**
- **Studio 5000 v30 ** may have **minor quirks** when working with older CompactLogix projects.
- Some **third-party drivers or protocols** may require **additional configuration**.
6. **Higher Upfront Cost Than Basic PLCs**
- More expensive than **basic microPLCs (e.g., Siemens S7-1200, Mitsubishi FX)** but **less expensive than ControlLogix**.
- **Module costs add up** if expanding I/O significantly.
7. **Physical Size & Installation Constraints**
- **Bulkier than microPLCs**, requiring **more rack space** in control panels.
- **12-slot backplane** may be **overkill for simple applications**, leading to **unused slots**.
8. **Dependence on Rockwell s Proprietary Ecosystem**
- **Less open-standard flexibility** compared to **Siemens, Mitsubishi, or Schneider Electric PLCs**.
- **Third-party module support** may be limited outside Rockwell s ecosystem.
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### **Conclusion**
The **Allen-Bradley 1738-485ASC-M12** is a **strong mid-range PLC** ideal for applications requiring:**Modular I/O expansion** (12 slots)
**EtherNet/IP networking** for industrial automation
**ASCII/serial communication** for legacy or non-Rockwell devices
**Studio 5000 compatibility** with Rockwell s ecosystem
**Reliable, industrial-grade performance**
However, it may **not be the best choice** if:**High-speed motion or advanced I/O** is required (needs additional modules)
**Budget is tight** (basic microPLCs may suffice)
**Open-standard flexibility** is preferred (consider Siemens, Mitsubishi, or Schneider)
**Future-proofing is critical** (newer **CompactLogix 5480/5580** may be better)
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### **Recommendation**
**Buy the 1738-485ASC-M12 if:**- You need a **reliable, modular PLC** with **EtherNet/IP and serial communication**.
- Your application requires **12 I/O slots** for expansion.
- You are **already using Rockwell Automation s ecosystem** (FactoryTalk, Studio 5000).
- You need **ASCII/serial connectivity** for legacy equipment.
**Consider alternatives if:**- **High-speed motion or advanced I/O** is needed **ControlLogix 5570/5580** or **CompactLogix 5480**.
- **Budget is limited** **Allen-Bradley 1769-L32E (microPLC)** or **Siemens S7-1200**.
- **Open-standard protocols (Modbus TCP, OPC UA)** are required **Schneider Electric Modicon, Siemens S7-1500, or Mitsubishi FX5U**.
- **Future upgrades** are a priority **CompactLogix 5480 (USB, more slots, better performance)**.
**Final Verdict:**The **1738-485ASC-M12 remains a solid choice** for **mid-range industrial automation** where **Rockwell s ecosystem and modularity** are key. However, **evaluate newer models** if long-term scalability is a concern. Always **verify module availability and software compatibility** before purchasing.
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ALLEN BRADLEY 1738-485ASCM12 / 1738485ASCM12 USED SPECIALTY I/O MODULES, 1738 ARMORPOINT, SERIAL MODULE, LINK INTERFACE CHANNEL - RS485, DC MICRO M12.