MTConnect or a stack-light monitor?
They answer different questions. MTConnect, or any other way of reading the control directly, tells you what the control knows. AndonTap tells you what the stack light and the spindle are doing. Many shops are best served by some of each.
- A list of your machines, with the control and its age for each
- Which of them have a working network port and a data interface you are licensed to use
- The questions you want answered: utilization and downtime, or program, alarm and tool detail
- Where the data has to land: Kepware, a PLC, SCADA, an MES or a monitoring package
Two different sources of truth
MTConnect is an open standard for reading data from machine tools in a common vocabulary. Where a control supports it, directly or through an adapter, a client can read what the control itself knows, which can include execution state, the active program, alarms and more, depending on the control and adapter. Control builders also offer their own interfaces, and many of the same points apply to those.
AndonTap reads signals outside the control: the lamp wires of the stack light, up to two clip-on current transformers, and 24 VDC machine signals (inputs 5-8, from firmware 1.7). It works out the machine state from ordered rules and serves state, counts and run times over Modbus TCP and EtherNet/IP. It does not speak MTConnect and does not talk to the control.
When the control's own data is the better choice
- You need detail only the control has: program names, alarm numbers and text, overrides, tool and part information. A stack light cannot carry any of that.
- The machine already supports it and it is on your network. If the interface is there and licensed, reading it adds no hardware in the cabinet.
- Your software expects it. If your monitoring package, MES or analytics tool is built around MTConnect, feed it MTConnect where you can.
- Newer, uniform fleets. Several machines on the same current control are the easiest case for a control-level interface.
When a stack-light and CT monitor fits better
- Older machines. No Ethernet, no supported interface, or an option that is no longer offered. If there is a stack light and a spindle motor, there is something to read. See monitoring an older CNC.
- Mixed fleets. Different builders and control generations, each with its own adapter or option. AndonTap is the same box with the same register map on every machine, so one Kepware template or one Logix UDT covers the floor.
- Equipment beyond the CNCs. Other machines with a stack light or a motor feed can be read the same way.
- Cutting, not just in cycle. The spindle CT reports stopped, turning or cutting from the motor current, and keeps cut time separate from spindle on time. That is measured at the wire, independent of what the control reports.
- A PLC or Modbus world. If your plant's data already flows through Kepware, Ignition or Allen-Bradley PLCs, Modbus TCP and EtherNet/IP drop straight in. See the Kepware and Studio 5000 guides.
- Nothing to change on the machine. No control option, no parameter changes, no PLC program. The inputs sit in parallel with the lamps and draw about 2 mA; the CT clips around one conductor.
- No cloud. The unit is a server on your plant network. A new unit sends nothing until it is given an address.
Side by side
| Control data (e.g. MTConnect) | AndonTap | |
|---|---|---|
| Source | The control | Stack-light wires, current transformers, 24 V signals |
| Machines covered | Controls that support it, directly or with an adapter | Anything with a stack light or a motor feed to clamp |
| Detail | Whatever the control and adapter expose | State, spindle level, counts, on and flash times, seconds in each state |
| Install | Network connection and, on some controls, an option or adapter | A DIN-rail module and wiring in the cabinet |
| Output | MTConnect for MTConnect clients | Modbus TCP (port 502) and EtherNet/IP |
| Consistency across a mixed fleet | Depends on each control and adapter | Same register map on every unit |
Using both
The two are not exclusive, and on a floor of mixed ages they often sit side by side:
- Split by machine. Read the newer controls directly; put AndonTap on the machines that cannot be read. Normalize both in the layer above, for example in Kepware, Ignition or your MES, so every machine reports a state in the same terms.
- Both on one machine. The control says what program is running; the spindle CT says whether it is cutting. AndonTap's rules can also use the lamps and CT2 (a coolant pump, conveyor or hydraulics) to describe states the control does not report the way you want.
- Line them up by name. Each unit serves its machine name and asset ID as data, so records from both sources can be matched to the same work centre.
A practical way to decide
- Sort the machine list into three groups: readable today, readable with an option or adapter, not readable.
- Decide what you need from each group. For utilization and downtime, stack light and spindle current are often enough. For program-level detail, you need the control.
- Pick the source per machine, and agree one set of state names for all of them.
- Pilot one machine of each kind, and compare what each source reports against what the operators see.
Weighing a PLC on each machine instead? See Why not a PLC? Full specifications are on the product page and in the user manual.
See what a stack-light monitor reports
The demo runs the real setup app on a simulated machine, with the live state, spindle level and register map.