How to Collect Data from CNC Machines: Fanuc, Siemens, and Mazak

Last updated: June 2026 · 11 min read

Your CNC Machine Is a Gold Mine of Data

Every CNC machine on your shop floor knows exactly what it's doing — spindle speed, axis positions, feed rate, tool life, alarm status, part count, cycle time. This data is sitting inside the controller, waiting to be extracted. The question is: how do you get it out?

The answer depends on which CNC controller you have. This guide covers the three most common controllers in mid-size factories: Fanuc, Siemens SINUMERIK, and Mazak, plus a universal approach for everything else.

Fanuc CNC: FOCAS Protocol

Fanuc is the world's most popular CNC controller, installed on millions of machines. Most modern Fanuc controllers (16i, 18i, 21i, 30i, 31i, 32i, 0i-D, 0i-F series) support FOCAS (Fanuc Open CNC API Specifications) — a built-in Ethernet communication library.

What You Can Read via FOCAS

Machine status — Running, stopped, alarm, emergency stop
Axis positions — All axes (X, Y, Z, etc.) in real-time
Spindle data — Speed, load, temperature
Program info — Current program number, sequence number, block count
Tool data — Tool life, tool number, wear offsets
Alarm history — Alarm codes, timestamps, severity
Production data — Part count, cycle time, power-on time
PMC data — Internal ladder logic signals (custom data)

How to Enable FOCAS

Check if FOCAS is enabled. On the CNC, go to SYSTEM → ETHPRM. If you see TCP/IP parameters, FOCAS is available. If not, you may need a Fanuc option license (typically $500-1500 from your machine builder).

Configure Ethernet. Set a static IP address on the CNC's Ethernet port. Note the port number (default: 8193 for FOCAS).

Connect the gateway. Plug an edge gateway into the same network switch. Configure the gateway with the CNC's IP address and select the Fanuc FOCAS driver.

Map data points. Select which FOCAS functions to poll. Start with: machine status (cnc_statinfo), alarm status (cnc_alarm), and part count (cnc_rdparam).

Common Gotchas

FOCAS requires a wired Ethernet connection — WiFi is not reliable enough for real-time data
Some older controllers need a PCMCIA Ethernet card (Fanuc Option C720 or similar)
FOCAS is read-only by default — writing to the CNC requires additional safety considerations
Polling rate should be 100ms to 1 second — faster polling can slow down the CNC's internal processing

Siemens SINUMERIK: OPC UA Native

Siemens took a different approach. SINUMERIK 840D sl and ONE controllers have OPC UA built in — no extra hardware or licenses needed for basic data access.

What You Can Read via OPC UA

NC variables — Axis positions, spindle speed, feed override, program number
Machine data — All MD parameters (hundreds of data points)
PLC variables — Any signal from the integrated SIMATIC S7 PLC
Drive data — Servo load, temperature, status (via DRIVE-CLiQ)
Alarm system — Active alarms, alarm history, diagnostic messages
Tool management — Tool list, tool life, wear data

How to Enable OPC UA on SINUMERIK

Check firmware version. SINUMERIK 840D sl needs firmware 4.7+ for OPC UA. SINUMERIK ONE has it from the start.

Enable OPC UA server. In the SINUMERIK HMI: Setup → Network → OPC UA → Enable. Set security policy (we recommend "Sign & Encrypt" for production).

Configure access rights. Create user accounts with appropriate read permissions. Don't use the default admin account for data collection.

Connect via gateway. The gateway's OPC UA client connects to the SINUMERIK's OPC UA server. Browse the node tree and subscribe to the variables you need.

Advantages over Fanuc

No additional license cost — OPC UA is included in the base SINUMERIK package
Standard protocol — works with any OPC UA client, not just vendor-specific software
Rich data model — data is self-describing with names, types, and units
Built-in security — authentication, encryption, and audit logging

Mazak: MTConnect + Smooth API

Mazak CNC machines support MTConnect — an open, royalty-free protocol specifically designed for manufacturing data collection.

How MTConnect Works

MTConnect uses HTTP/XML. A small agent (software) runs on the CNC or a connected PC, exposing machine data as a structured XML stream. Any system can request data by sending HTTP GET requests to the agent.

What You Can Read

Execution state (running, idle, stopped)
Spindle speed, feed rate, axis positions
Program name and line number
Part count and cycle time
Alarm and event messages

Enabling MTConnect

Newer Mazak machines (SmoothX, SmoothG controllers) come with MTConnect agent pre-installed. For older machines, you may need to install the Mazak MTConnect adapter on a connected PC. The adapter communicates with the CNC via Mazak's proprietary protocol and exposes data via MTConnect.

Universal Approach: For Any CNC Controller

What if your CNC doesn't support FOCAS, OPC UA, or MTConnect? You still have options:

Option 1: Macro B Output

Many CNC controllers support custom macro programming. You can write a macro that outputs data (part count, cycle time, alarm codes) to a serial port or Ethernet socket at the end of each cycle. This works on virtually any CNC with macro capability.

Option 2: I/O Monitoring

Every CNC has digital I/O signals — machine ready, cycle start, cycle end, alarm. You can tap into these signals with a simple digital input module connected to a gateway. This gives you basic status monitoring without touching the CNC software.

Option 3: Current Sensing

A current transformer (CT) clamp on the spindle motor power cable can tell you when the machine is cutting, idle, or off. This is the least invasive method — no electrical connection to the CNC at all.

Choosing the Right Approach

Controller	Best Method	Data Richness	Setup Difficulty
Fanuc 0i/16i/18i/30i	FOCAS	⭐⭐⭐⭐⭐	⭐⭐
Siemens SINUMERIK	OPC UA	⭐⭐⭐⭐⭐	⭐⭐
Mazak SmoothX/G	MTConnect	⭐⭐⭐⭐	⭐
Any CNC (basic monitoring)	I/O + Current	⭐⭐	⭐
Any CNC (full monitoring)	Macro B Output	⭐⭐⭐	⭐⭐⭐

FAQ

Q: Will data collection slow down my CNC?: No, if done correctly. FOCAS, OPC UA, and MTConnect are designed for background data extraction. Polling rates of 500ms-1s have zero impact on CNC performance. Avoid polling faster than 100ms.
Q: My Fanuc doesn't have FOCAS enabled. What do I do?: Contact your machine builder (OEM) to purchase the FOCAS option. Alternatively, use the I/O monitoring approach for basic status, or the Macro B approach for cycle data.
Q: Can I collect data from multiple CNC machines with one gateway?: Yes. A single edge gateway can typically connect to 10-50 CNC machines over Ethernet, depending on the data polling rate and number of data points per machine.
Q: Do I need to stop production to install data collection?: For Ethernet-based methods (FOCAS, OPC UA, MTConnect): no downtime needed. For I/O monitoring: a brief stop (10-15 minutes) to install current sensors or tap into digital signals.
Q: What about Heidenhain, Mitsubishi, or Haas controllers?: Heidenhain supports DNC/DCI protocol. Mitsubishi supports MELSEC communication. Haas supports MTConnect (newer models) or serial output. Each has its own approach — contact us with your specific controller model for detailed guidance.