What sits between the machine and the invoice
There are more layers than the office sees, and each one is a place where a project can stall.
- The PLC and the machine. Siemens, Rockwell, Omron or Schneider controllers know the truth: what is being made, at what speed, how many parts and when the line stopped. That information is usually there and stays there. We program PLCs and make machines — CNC, robots, conveyors — talk to each other, as well as writing the management software.
- The protocol. OPC UA is the most widespread standard: the OPC Foundation defines it as a platform-independent architecture that provides the infrastructure for interoperability across the enterprise, machine to machine and machine to enterprise. Alongside it live Modbus TCP, MQTT for telemetry and vendor fieldbuses such as Profinet or EtherNet/IP. Few plants have a single protocol; most have whatever twenty years of purchases left behind.
- The gateway. A device on the shop floor that reads from the controllers, normalises and delivers — so the ERP doesn't need to know anything about fieldbuses, and data survives when the network or the server goes down.
- The MES. The ISA-95 model places it at level 3: production orders, traceability and shop-floor records. ERP and MES don't compete. The ERP decides what to make, for whom and at what cost; the MES executes and records how it was made, batch by batch and machine by machine, and returns the data to the ERP as real consumption, time and cost. In mid-sized companies this layer is often a spreadsheet and a person with a good memory.
- The ERP. Off-the-shelf or custom, it's where production becomes cost, invoice and stock. If you're weighing a replacement, see custom ERP.
What gets recorded without anyone typing it
Units produced per order, stoppages and their duration, material consumed, scrap, cycle times and who was on the line. Every record carries its time and its order, so the question "what did this batch really cost?" stops needing a meeting.
What an AI agent decides with that data
An order comes in; an agent decides which line, in what sequence and with what material, using your criteria and margins; the machine executes; everything is recorded. When a machine stops, the agent re-plans and warns whoever needs to know. The decision rules are yours, written down, and every decision is traceable.
Why these integrations fail
Rarely because of the protocol. They fail because nobody agreed what "finished" means: finished for the machine, for quality, for the warehouse and for invoicing are four different moments. Defining that before writing a line of code is half the project.
What it costs and how long it takes
The first module live and connected to real operations takes 8 to 14 weeks from signing; a first phase for a company of 30–80 employees runs €40,000–120,000. Every plant is different, so the quote comes after the NDA and the analysis. More in custom software.
How we start
Always the same way. Day zero: an NDA signed before you show us anything. Then the Nexus team analyses your operation and delivers a report with the exact changes, prioritised by impact on your P&L. Then you decide. Nexus Elite AI is an engineering boutique in Barcelona: two people, no juniors, no subcontractors, and never more than seven clients at a time. Apply and we reply within 24 business hours; if there is no fit, we tell you in writing.
Frequently asked questions
Do I need an MES, or is connecting the PLC to the ERP enough?
It depends on how many decisions happen between the machine and the invoice. If an order enters, runs on one line and leaves, a gateway writing to the ERP may be enough. With sequencing, batches, traceability, in-process quality or several machines sharing an order, those rules need a home, and that home is an MES — off-the-shelf or custom — not ERP customisations.
Can an old PLC be connected to the ERP?
Usually yes. Older controllers that don't speak OPC UA can be read through Modbus, vendor protocols or a gateway that translates. What we check first is what data the controller actually holds and how reliable it is.
Which PLC brands do you work with?
Siemens, Rockwell, Omron and Schneider are the most common in the plants we are built for, with OPC UA, Modbus TCP, MQTT, Profinet and EtherNet/IP. The brand matters less than documenting what each machine knows.
Does this replace my ERP?
Not necessarily. Most projects connect the shop floor to the ERP you already have. Replacing it only makes sense when it models your operation badly; that decision comes out of the analysis, not before.