Build vs Buy a Fanuc Connector: Real Costs

The "build vs buy" question on a Fanuc connector is rarely answered honestly inside an integrator company. The senior engineer who'd build it underestimates the long tail. The CFO sees only a license fee and asks why we're "paying for something we could write." This article gives both sides the numbers they need.

TL;DR: When Building Makes Sense, When It Doesn't

Build your own Fanuc connector when

1. you have at least one engineer with prior Focas experience
2. you commit to Fanuc as a strategic specialty for 3+ years
3. you accept that you will not cover other CNC brands the same way.

Otherwise, license an OEM library or use a CNC-specialized platform — the build path's break-even point sits well past most integrator project pipelines.

What "Building Your Own" Actually Involves

Getting Access to the Focas Library

Focas is Fanuc's official C/C++ library for reading data from Fanuc CNC controllers. Access is via Fanuc's developer programs — typically MTConnect Adapter Kit, FOCAS-AC kit, or direct partnership. You'll sign a license agreement with redistribution restrictions. See OEM Protocol Licensing Guide for the legal terrain. This is non-negotiable: there's no legitimate path to Focas data without Fanuc's library.

Wrapping Focas Calls (C/C++/.NET/Java)

Focas exposes 600+ functions. A useful integrator-level API needs 30–50 of them, covering machine status, alarms, modal codes, axis positions, spindle data, program info, tool data, and macro variables. Each function has version sensitivity (Focas 1 vs Focas 2, vs library version 4.x) and controller-series sensitivity. See Focas tech guide and Focas 1 vs 2.

Handling Variants Across Controllers (0i, 30i, 31i, 32i)

Each Fanuc controller series exposes slightly different Focas function support. Your code needs runtime feature detection or per-series branching. The 0i Mate, 0i-D, 30i-A, 30i-B, 31i-A, 31i-B5, 32i are all common in customer fleets. Skip series detection and your connector breaks on customer site #2.

Connection Pooling and Reconnection Logic

Focas connections drop on machine power cycles, network glitches, controller reboots after alarm conditions. Production-quality connector code handles reconnect with backoff, distinguishes transient from permanent failures, and reports machine state when offline.

Data Modeling and Tag Hierarchy

Raw Focas returns are unhelpful — you need to map them to a tag tree the rest of your stack can consume. Modal G-codes need decoding. Alarm IDs need cross-referencing to alarm text tables. Tool numbers need offset lookups. This is dozens of small problems, each easy in isolation, all of which add up.

Storage, Buffering, and Network Outage Handling

Customer networks fail. WAN links drop. Your connector needs local buffering with at-least-once delivery to whatever's downstream. SQLite, RocksDB, or a circular file are all viable. None of them are free hours.

Real Development Time: A Project Diary

These ranges assume an experienced industrial software developer. Junior or part-time staff: multiply by 2–3.

Week 1–2: Focas Library Setup and First Connection

Get the Focas SDK from Fanuc, set up build environment, write a "hello world" that reads machine ID. 40–80 hours including the inevitable license-paperwork delays.

Weeks 3–6: Adding Each Data Type

Spindle load, axis positions, modal codes, active program, alarm queue, tool data, macro variables, status flags. 120–200 hours covering ~30 data points cleanly with error handling.

Weeks 7–10: Multi-Machine Testing

Get access to 3–5 different controller series. Find the variants. Add detection logic. Test reconnection behavior. 80–160 hours.

Weeks 11+: The Long Tail (Edge Cases, Old Controllers)

Older 0i Mate that doesn't expose the function you assumed. 18i with quirky alarm format. 35i with a feature you've never seen. This is where most internal builds spend the next 6 months. Realistic: 200–400 hours over a year as production deployments surface new cases.

Total to "production ready for our integrator's projects": 440–840 hours over 6–12 months, plus access to 5+ real Fanuc controllers for testing.

Cost Model: Build Path

Initial Development

At $90–$140/hour fully-loaded engineer cost: $40,000–$120,000 for a production-grade Fanuc-only connector.

Ongoing Maintenance per Year

New Focas library versions, new controller series, customer-specific edge cases, security patches. 120–240 hours/year = $11,000–$34,000/year.

Per-Project Customization

Each customer project still needs configuration, tag mapping, validation. The "we built it" doesn't eliminate per-project hours. 20–60 hours/project on top of pure deployment.

Opportunity Cost: What Else Could Your Team Do?

Engineers building infrastructure aren't shipping projects. If your average integrator project is $80–$150k and your engineers ship 4–6/year, the build-month tax is real revenue.

Cost Model: OEM Library Path

License Fee Structure

Commercial CNC connectivity platforms license either per-machine, per-server, or per-site. For a Fanuc-focused integrator running 5 simultaneous projects with 20 machines each (100 active machines): $15,000–$50,000/year depending on vendor and partner discount.

Time-to-First-Project

Typically days, not months. Tag templates, machine profiles, dashboards exist. Per-project deployment is configuration, not coding.

Vendor Maintenance Includes

Focas library upgrades, new controller support, edge-case fixes, security patches, OS compatibility. The vendor amortizes this across all customers, which is why it's cheaper than your share alone.

Break-Even Analysis

If you build, you spend $40,000–$120,000 upfront plus $11,000–$34,000/year. If you license, you spend $15,000–$50,000/year with zero upfront. Even at the cheapest build numbers and most expensive license, the build path requires at least 2–3 years of consistent volume to break even — and that ignores opportunity cost and quality risk.

The only scenarios where build pays off: - You ship 50+ Fanuc-only deployments/year for 5+ years. - You are a pure-Fanuc specialist with deep technical differentiation. - You're embedded as an OEM-aligned partner with Fanuc-supplied resources.

For everyone else, the math doesn't work.

Hidden Risks of Building Your Own

Fanuc License Compliance

Distributing Focas library binaries to customers without a redistribution agreement is a license violation. Vendors handle this; in-house builds often don't realize it's an issue until audited. See OEM Protocol Licensing Guide.

Single-Developer Dependency

The engineer who built it leaves. The next person can't ship to a new controller series. Your delivery capability collapses with one resignation.

No Coverage of Other Brands

You wrote a Fanuc connector. Customer asks for Mazak too. Now you write a Mazak connector. Then Heidenhain. Then Mitsubishi. Each one is the same investment again, with the same long tail.

When Building Your Own Still Makes Sense

• You're a true Fanuc specialist with strategic differentiation.
• You need a feature no commercial vendor offers (extremely rare).
• You're deploying at FAANG-scale (100,000+ machines) where vendor licensing simply doesn't price.
• Regulatory or sovereignty constraints prohibit using third-party software (rare; typically defense or specific government work).

Frequently Asked Questions

Can I get Focas without paying Fanuc?

No legitimately. Focas is Fanuc's proprietary library. Any path to Focas data goes through a Fanuc license — either yours, your vendor's, or your customer's existing arrangement.

Can I use MTConnect to skip Focas entirely?

For Fanuc, MTConnect requires the FANUC MTConnect Adapter (still using Focas under the hood) or a third-party adapter. You haven't avoided Focas — you've put a wrapper on it. See MTConnect.

What about open-source Focas wrappers on GitHub?

Many exist. Most are abandoned or proof-of-concept. None remove the licensing requirement. Production deployment with an unlicensed wrapper is a legal exposure.

Is the Fanuc PMC reading easier than Focas?

PMC reading via the same Focas library is part of the same scope. Direct Ethernet reads (pmc_rdpmcrng) are easier than parsing Focas modal codes, but it's the same library and same license.

How long does an experienced engineer really need?

For a Fanuc-only, 30-data-point, multi-controller-series, production-quality connector with reconnection, buffering, and tag mapping: realistically 6–12 months of part-time work or 3–4 months full-time. Plus ongoing maintenance forever.

What if my engineer has built one before?

Halve the timelines. But verify they're allowed to reuse code from a prior employer — IP claims here are messy.

Can I outsource the build?

Yes, but you're now buying connector development services from a vendor anyway — at custom-project rates higher than commercial product licenses.

Does MDCplus include Focas licensing?

Yes. MDCplus's product license covers Focas redistribution to customer deployments. You don't sign a separate Fanuc agreement.

Try MDCplus's Pre-Built Fanuc Layer

Save the 6–12 months and the ongoing maintenance overhead. Request a demo and we'll show MDCplus reading from your real Fanuc controllers within an hour. Or try MDCplus free on a single Fanuc machine first.

Related:

• CNC Connectivity Software for Integrators (Hub)
• OEM Protocol Licensing Explained
• Focas Tech Guide for Fanuc
• Focas 1 vs Focas 2 Comparison
• Open-Source vs Commercial CNC Connectivity
• CNC Data Collection Cost Calculator

About MDCplus

Our key features are real-time machine monitoring for swift issue resolution, power consumption tracking to promote sustainability, computerized maintenance management to reduce downtime, and vibration diagnostics for predictive maintenance. MDCplus's solutions are tailored for diverse industries, including aerospace, automotive, precision machining, and heavy industry. By delivering actionable insights and fostering seamless integration, we empower manufacturers to boost Overall Equipment Effectiveness (OEE), reduce operational costs, and achieve sustainable growth along with future planning.