What Is an MTConnect Agent?
The agent is the part of MTConnect your monitoring software actually talks to. The adapter is the part that talks to the machine. Here is what each does, where they run, and how to tell what your shop needs.
If you are setting up MTConnect monitoring, two words come up immediately: agent and adapter. They are easy to confuse and important to get right, because they determine what you need to install and who needs to do it.
Your monitoring software talks to the agent. The agent gets its data from the adapter. The adapter talks to the machine.
The agent in one paragraph
An MTConnect Agent is a small server. It receives machine data, organizes it into the standard MTConnect information model, keeps a rolling buffer of recent changes, and answers HTTP requests from client applications — /probe for the device description, /current for latest values, and /sample for the history of changes. It is the single point that monitoring software connects to.
The adapter in one paragraph
An adapter connects to the machine control using whatever the control natively supports, reads the values that matter (execution state, part count, program, alarms, and more), and sends them to the agent in a simple text stream — commonly the SHDR format over port 7878. The adapter is the piece that knows the specific control.
Agent vs adapter side by side
| Adapter | Agent | |
|---|---|---|
| Talks to | The machine control | Adapters and client applications |
| Knows about | One control type's native interface | The MTConnect standard model |
| Output | Simple data stream (often SHDR) | MTConnect XML or JSON over HTTP |
| Typical port | 7878 (to the agent) | 5000 (to clients), configurable |
| How many | Usually one per machine | One can serve many machines |
| Monitoring software connects to it? | No | Yes |
Where agents and adapters run
Built into the control. Many current controls include MTConnect internally, sometimes as a paid option. The machine itself answers MTConnect requests on its IP address.
On the machine's PC side. PC-based controls can run an adapter and agent as software on the control's own computer.
On a shop PC or gateway. For machines without built-in support, adapters run on a separate PC or edge device that connects to each control, and an agent on the same PC serves all of them.
Do you need to install an agent?
Work through these questions per machine:
- Does the control include MTConnect? Check the options list or ask your dealer. If yes, it may only need enabling.
- Is there already an agent on your network? Previous monitoring or MES projects often leave one behind. Try
http://<ip>:5000/currentin a browser. - If not, is there an adapter for this control? Integrators and open-source projects provide adapters for many controls.
- Then run an agent — on a PC or gateway — to serve that adapter's data.
Already Have MTConnect? covers the first two situations, and Connect a CNC Machine walks through the full checklist.
How monitoring software uses the agent
FEAI Machine Monitor connects to each agent with read-only HTTP GET requests:
/probeto learn which devices and data items exist/currentfor the latest values/sampleto receive every change since the last request, so the timeline has no gaps
It stores the results locally on the Windows PC and builds status, timelines, utilization, OEE, and downtime from them. It never writes back to the agent or the machine.
The agent's buffer — why it matters
Agents keep a fixed-size buffer of recent changes, each with a sequence number. Clients ask for "everything since sequence N." If the client stops polling for longer than the buffer covers, older changes are gone. Good client software polls frequently and detects gaps. If you see holes in a timeline after a network outage, the buffer is usually the reason.
Running an agent well
If your shop runs its own agent PC, a few habits keep monitoring reliable:
- Keep it on. Disable sleep and schedule Windows updates outside production hours.
- Start automatically. Run the agent and adapters as services that start when the PC boots.
- Use fixed addresses for the agent PC and every machine it reads.
- Write it down. Record which machines each agent serves, its port, and who supports it.
Common agent problems
| Symptom | Likely cause |
|---|---|
| Browser cannot reach the agent | Wrong IP or port, agent not running, firewall |
| Agent answers but Availability is UNAVAILABLE | Adapter not connected or machine powered off |
Data items missing from /probe | Agent device file does not define them |
| Data items present but always UNAVAILABLE | Adapter not sending those values |
| Gaps in history | Client polled too slowly for the agent's buffer |
How to Test an MTConnect Connection walks through fixing each one.
Have an agent answering? Start free — 2 machines and connect it.
FAQ
What does an MTConnect agent do?
It collects data from one or more adapters or machines, organizes it into the standard MTConnect information model, keeps a buffer of recent changes, and serves the data to client applications over HTTP.
What is the difference between an MTConnect agent and adapter?
The adapter connects to the machine control and translates its native data into a simple stream. The agent receives that stream and serves standardized MTConnect data to clients. Clients talk only to the agent.
Do I need to install an MTConnect agent?
Not always. Some controls include an agent, and some shops already run one. Machines without built-in support usually need an adapter and an agent, which can run on a PC or gateway.
Can one agent serve multiple machines?
Yes. A single agent can publish many devices, each with its own data items, from one network address.
Where can I get an MTConnect agent?
Some controls provide one built in or as an option. The MTConnect Institute maintains an open-source reference agent. Integrators and machine dealers also provide agent and adapter packages.
Does FEAI Machine Monitor include an agent?
No. FEAI is a client that connects to an existing accessible MTConnect Agent or compatible endpoint.