Before a machine’s data can appear on a dashboard, it needs a way to get there. That journey begins with a communication protocol: the language that defines how a machine expresses its status, and how software listens to it. Understanding the major protocols in use today helps manufacturers make smarter decisions about connectivity hardware, software compatibility and long-term flexibility.
Shop Floor Automations works across all of these protocols to help you choose, configure and deploy the right combination for your specific machines, IT requirements and environment.

MTConnect is natively supported by most modern CNC controls from major manufacturers including Mazak, DMG Mori, Okuma, Makino, Hurco and others. Machines with older or proprietary controls, such as legacy Fanuc, Siemens, Mitsubishi or Heidenhain controls, can be connected via MTConnect adapters: hardware or software shims that translate the machine’s native output into MTConnect-compliant data streams.

Shop Floor Automations supplies, configures and deploys MTConnect adapters for a wide range of legacy controls, allowing manufacturers to achieve standardized data collection across both new and legacy equipment without replacing functional machines.

MTConnect is intentionally read-only, meaning software can listen to machine data but cannot send commands back to the machine through the MTConnect interface. For machine monitoring and OEE purposes, this is not a limitation but a security feature. The read-only nature ensures that monitoring software cannot inadvertently affect machine operation. For applications that require bidirectional communication, such as sending CNC programs to a machine, other protocols or dedicated DNC connections handle that function alongside MTConnect monitoring.

The two protocols are complementary rather than competitive, and each has a distinct role:

• MTConnect is specific to manufacturing equipment, read-only and optimized for collecting structured machine tool data in a consistent semantic format. It is the right choice when the primary goal is machine monitoring and OEE data collection from CNC machines.
• OPC-UA is a broader industrial communication framework, supports bidirectional communication and is used across a wider range of devices including PLCs, SCADA systems, robotics, process equipment and enterprise software. It is the right choice when the integration requirement goes beyond machine monitoring, such as feeding data to MES, ERP or cloud analytics platforms, or when control-level write access is required.

In practice, many modern manufacturing environments use both: MTConnect for standardized machine tool monitoring and OPC-UA as the integration backbone connecting shop floor data to higher-level systems.

Modbus is a serial communication protocol originally developed by Modicon (now Schneider Electric) in 1979. Despite its age, it remains one of the most widely deployed industrial communication protocols in the world, primarily because of its simplicity, robustness and the sheer volume of devices that still use it. Modbus operates TCP (over Ethernet) commonly in modern deployments.

In a typical mixed-equipment manufacturing environment, Modbus, MTConnect and OPC-UA often coexist. Newer CNC machines communicate via MTConnect or OPC-UA, while legacy machines, PLCs and sensors communicate via Modbus. Shop Floor Automations designs and implements connectivity architectures that bring all of these data streams together into a single monitoring platform to ensure that every asset on your floor, regardless of age or control type, contributes to your production visibility.

MTConnect (ANSI/MTC1.4-2018) is an open, royalty-free communication standard developed specifically for manufacturing equipment. Introduced in 2008 and maintained by the Association for Manufacturing Technology (AMT), it defines a structured, standardized data model and a read-only streaming protocol that allows CNC machines, robots and other shop floor equipment to share data with software applications in a consistent, machine-agnostic format.

As a common vocabulary, MTConnect defines shared element names like Execution, Program, PathFeedrate, SpindleSpeed and Alarm across device manufacturers. Software that speaks MTConnect can read from any compliant machine without needing a brand-specific adapter.

MTConnect can capture a broad range of machine data depending on the control’s capabilities and the adapter configuration, including:

• Machine execution state (Active, Stopped, Interrupted, Feed Hold)
• Controller mode (Automatic, Manual, MDI)
• Active program name and block number
• Spindle speed and load
• Path feed rate and feed rate override
• Axis positions
• Part count and tool data (where available)
• Alarm and fault codes

OPC Unified Architecture (OPC-UA) is a platform-independent, service-oriented communication framework developed by the OPC Foundation for industrial automation and manufacturing. Unlike MTConnect, which is specific to machine tools and read-only, OPC-UA is a general-purpose industrial communication standard that supports bidirectional data exchange between a wide range of devices, systems and applications.

OPC-UA operates on a client-server or publish-subscribe model, where an OPC-UA server exposes data nodes, like variables, objects, methods and events, that clients can read, write, subscribe to or call. It includes built-in security mechanisms including encryption, authentication and certificate-based access control, making it well-suited for aerospace, defense and enterprise-level deployments where data security matters.

OPC-UA support is increasingly native on modern CNC controls (including Siemens SINUMERIK 840D, Heidenhain TNC 7), industrial PLCs (Siemens S7, Allen-Bradley/Rockwell PLCs via companion specifications), collaborative and industrial robots and smart sensors and edge devices. SFA can assess your machine inventory for OPC-UA readiness and deploy OPC-UA gateway hardware where native support is not available.

Modbus is fundamentally a register-based protocol: it reads and writes values in predefined memory registers on a device. This makes it powerful for capturing numeric values like spindle RPM, temperature, position, counts and discrete states, such as on/off, open/closed and fault/normal. What Modbus does not provide on its own is semantic context: a Modbus register value of “1” in register 40003 only means something if you know what that machine’s manufacturer mapped to that address. SFA’s implementation work includes mapping register addresses to meaningful data points in the monitoring software, transforming raw register reads into labeled, actionable events.

Yes. Connecting legacy machines is one of SFA’s core specialties. Older controls with RS-232 serial ports, parallel I/O outputs or basic relay signals can be connected using serial-to-Ethernet converters, I/O capture modules and Modbus-based hardware. This allows machines with no native MTConnect or OPC-UA support to transmit cycle status, spindle state and other data to Scytec DataXchange or Predator MDC, delivering unified production visibility across both new and legacy equipment.