What is an MES? MES vs ERP vs machine monitoring

What is an MES?

An MES, a manufacturing execution system, runs and records the work on the shop floor. It knows which order goes to which machine, who works on it, which material and tools it uses, what came out and whether it was good. It sits between the ERP, which plans orders and money, and the machines.

The industry group MESA described the eleven functions of an MES in 1997. The ISA-95 standard (IEC 62264) puts the MES on level 3, manufacturing operations management, between business planning on level 4 and the machines' own control below it.

What does an MES do?

The eleven functions MESA listed, in plain words.

Scheduling, the order in which jobs run on each machine.
Dispatching, releasing jobs to the floor.
Resources, which machines, tools and materials are free.
Documents, drawings, programs and work instructions at the machine.
Data collection, what machines and people report.
Labour, who worked on what, and for how long.
Quality, inspections and measurements, kept with the part.
Process management, the route a part takes from step to step.
Maintenance, planned upkeep and repairs.
Tracking and genealogy, which material, lot and serial number went into each part.
Performance analysis, how the work went against the plan.

An MES that does all eleven is a large system. Most offer a selection, and many are sold module by module.

How is an MES different from an ERP?

An ERP runs the business, with its quotes, orders, purchasing, stock, invoices and costs. It knows what you sold and when it is due. An MES runs the making. It knows which order is on which machine now, and how far it has got.

The ERP plans in weeks and days, the MES works in shifts and minutes. The two talk to each other. The ERP sends the orders, and the MES sends back the quantities made and the hours spent, so the ERP's costs are real ones.

What is machine monitoring?

Machine monitoring reads each machine's control. It sees whether the machine runs, waits or stands in alarm, which program it runs and how many parts it makes. Operators add why it stopped. From that you see, live, where the hours go, the real cycle time of every part and the OEE of every machine and shift.

Nobody has to book anything for it to work. The machine itself says what it does.

What does an MES do that machine monitoring doesn't?

An MES manages the work, its orders, routes, materials and people. Machine monitoring measures the machines, their running time, stops and reasons, cycle times and OEE.

Of MESA's eleven functions, machine monitoring does two in full, data collection and performance analysis. It does them from the control, not from people booking on and off jobs, so a stop nobody booked still counts. Good machine monitoring also covers part of four more, by showing which machines are free, counting who ran each machine, logging scrap with its reason and calling maintenance when a machine breaks down. Scheduling, dispatching, routes, documents and traceability stay an MES's.

What does an MES ask of a small manufacturer?

More than its licence. Before it shows anything, an MES needs four things.

Master data, a route with steps and standard times for every part, the work centres, the materials. A manufacturer with new parts every week keeps that up to date every week.
Booking at every step, by operators signing on and off each operation at a terminal by the machine. An MES only knows what people book.
A link to your ERP, in both directions, set up and kept working.
A project of months to choose, set up and train for, led by someone in your company.

For a plant that must trace every lot, or that runs the same parts through many steps, that pays off. For a manufacturer with ten machines that wants to know why they stand, it is a lot to ask first.

Which comes first?

Start from the question you need answered.

Where do my machine hours go? Why do machines stand? What does a part really take? Machine monitoring answers that from the first day, without anyone booking.
Customers want traceability per lot or serial number, or paperless instructions and inspections at every step? That is an MES.

Many manufacturers start with machine monitoring. It is quick to put in, it shows where the hours go, and so where an MES would pay off.

Can an MES and machine monitoring work together?

Yes. An MES plans with running times, stops and cycle times, and those are what machine monitoring measures. A manufacturer that starts with monitoring and exports those figures sets up its MES from what its machines really do, not from guesses.

Is Dextrolab an MES?

No. Dextrolab is machine monitoring. It shows every machine live, why it stopped, its OEE and its real cycle times, from the machine's control and the tablet at the machine. It doesn't plan or release orders, track material or keep lot traceability.

Sources

MESA International, MESA White Paper #02: MES Functionalities and MRP to MES Data Flow Possibilities, March 1997 (listing, read on 27 October 2026).
International Society of Automation, ISA-95 Standard: Enterprise-Control System Integration, isa.org, read on 27 October 2026.