Per-Machine, Per-Connection, or Site License? CNC Connectivity Pricing Models Explained

The pricing model on a CNC connectivity quote determines your project margin more than the headline number. Same software at the same per-unit rate can land at radically different total cost depending on which model the vendor uses. This article walks through the four common models, where each one wins, and how to negotiate the model - not just the price.

Quick Answer: Which Model Wins by Project Size

• Under 10 machines: per-machine usually cheapest; per-site overprices.
• 10–50 machines: per-machine still typically wins; per-connection becomes punishing.
• 50–150 machines: per-machine or per-site competitive; per-connection clearly worst.
• 150+ machines or multi-site: per-site or per-server models start winning; per-machine flat rates may need volume negotiation.

Per-connection is the worst model for any CNC-heavy project past 5 machines. Run the numbers carefully when a vendor proposes it.

The 4 Pricing Models You'll See

Per Connection / Per Tag

Each TCP session or each monitored data point counts. Every machine usually = 1 connection (sometimes more). Common with general-purpose OPC servers (Kepware, Matrikon).

Wins when: small projects with high data points per device (PLC-heavy SCADA). Loses when: many devices with moderate data each (typical CNC fleet).

Per Machine

Predictable per-CNC pricing. The data point count, brand, and protocol don't change the cost. Common with CNC-specialized platforms (MDCplus, MachineMetrics, Predator).

Wins when: clean machine count, predictable scaling, integrator-side budgeting. Loses when: customer has many small/auxiliary devices that count as "machines" but shouldn't.

Per Site / Per Server

Flat fee per physical site or per server instance, regardless of machine count. Common with SCADA platforms (Inductive Ignition) and enterprise MES (FORCAM).

Wins when: large machine counts on single site, customer values "unlimited" predictability. Loses when: single site with low machine count - flat fee overprices.

Subscription Tiers

Tiered SaaS pricing by machine count band, data volume, or feature set. Common with cloud-native vendors (MachineMetrics, modern entrants).

Wins when: machine count fits cleanly within a tier. Loses when: you're 10% over a tier break point - you pay for the next tier without using its capacity.

Hidden Cost Variables Buried in Each Model

The model alone doesn't tell you total cost. Watch for:

• Annual renewal increases - uncapped 8–12% annual increases compound.
• Connection / machine "growth charges" - surprise costs when adding the 51st unit.
• Driver suite vs individual driver pricing - buying drivers à la carte vs bundled.
• PSP / maintenance fees - typically 18–22% of license per year, sometimes mandatory.
• Cloud egress - per-GB charges that build up on data-heavy fleets.
• User seats - some vendors price by user, separately from machine licenses.

A "cheaper" model can land more expensive in year 3 with all variables included.

Math: Cost Curves on 10 / 50 / 200 Machines

Illustrative - verify with vendor quotes. Assumes no volume discount.

10 machines, single site, mixed brand: | Model | Year-1 license | |---|---| | Per-connection (Kepware-style) | $7,000–$14,000 | | Per-machine (MDCplus-style) | $4,000–$8,000 | | Per-site (FORCAM/Ignition-style) | $30,000+ | | SaaS tier (MachineMetrics-style) | $5,000–$10,000 |

50 machines, single site: | Model | Year-1 license | |---|---| | Per-connection | $25,000–$45,000 | | Per-machine | $20,000–$40,000 | | Per-site | $30,000–$50,000 | | SaaS tier | $25,000–$50,000 |

200 machines, multi-site (3 sites): | Model | Year-1 license | |---|---| | Per-connection | $90,000–$160,000 | | Per-machine | $80,000–$160,000 | | Per-site (3 × $50–80k) | $150,000–$240,000 | | SaaS tier (enterprise) | $100,000–$220,000 |

Per-connection's curve is steepest because the base cost compounds with driver and connection-tier surcharges.

How to Negotiate License Models with Vendors

Negotiate the model first, not the unit price. Vendors are often willing to switch models for the right deal - per-connection vendor will quote per-machine for a strategic customer; per-site vendor will quote per-machine for an SMB pilot.

Concrete tactics: 1. Ask for two quotes - model A and model B - on the same machine list. 2. Negotiate cap on annual increase (3–5% target, vs 8–12% standard). 3. Negotiate "growth license" - pre-paid additional machines at locked rate. 4. Ask for renewal discount commitment (15–25% off year-1 in years 2+). 5. If multi-year, ask for first-year discount in exchange for commitment.

For RFP-driven evaluations, the free RFP template includes pricing model sections that surface these answers.

Renewal Risk by Model

• Per-connection: highest risk - vendor controls connection definitions and can adjust counting in renewal.
• Per-machine: low risk - easy to verify, hard to game.
• Per-site: medium risk - site definitions can shift.
• SaaS tier: medium risk - tier breaks shift with vendor pricing changes.

Always lock the renewal terms in writing alongside the year-1 contract.

How MDCplus Licenses Work

MDCplus uses per-machine pricing. Each CNC = one license, brand-agnostic. License includes: - All native OEM protocols. - Built-in dashboards and analytics. - Multi-user access. - Standard support. - Updates and version upgrades.

Multi-site discounts available for 100+ machine deployments. Partner margin built into structure for integrator deals. [VERIFY: confirm current pricing tier and partner program details].

Frequently Asked Questions

What's a "connection" exactly in Kepware terms?

A simultaneous TCP session between KEPServerEX and a downstream device. Most CNC machines = 1 connection, with edge cases (redundant paths, multi-endpoint Siemens controllers, PLCs with subdevices). See Kepware Pricing for CNC.

Is per-machine always best?

Not always. For very high machine counts on single site, per-site can be cheaper. For low machine counts with rich data per machine, per-connection sometimes works.

Can I mix license models in one project?

Often, yes - different vendors for different equipment classes. CNC-specialized platform per-machine for CNCs + per-server SCADA platform for PLCs.

What's a fair renewal increase cap?

3–5% annual is reasonable for committed multi-year deals. 8–12% is standard but negotiable.

Should I worry about PSP / maintenance fees?

If they're 20% of license and mandatory for updates, yes - they're effectively a 20% perpetual surcharge. Factor into year-1 quote.

How do I avoid being trapped at renewal?

Lock renewal terms in writing during initial contract. Know the data export options (formats, retention, format compatibility). Maintain optionality.

Are unlimited site licenses really unlimited?

Read the fine print. "Unlimited tags" sometimes has data-rate caps. "Unlimited machines per site" sometimes has user-seat caps.

What model does MDCplus use?

Per-machine, brand-agnostic, all features included. Multi-site and volume discounts apply at scale.

Estimate Your License Cost

For your specific machine count and brand mix, request a demo and we'll provide an MDCplus quote against your project. Or run scenarios through the project cost calculator.

Related:

• CNC Connectivity Software for Integrators (Hub)
• Kepware Pricing for CNC
• Project Cost Calculator
• OEM Protocol Licensing
• RFP Template
• ROI 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.