For every machine that is not a CNC.

Presses, furnaces, moulding machines, packing lines and the conventional fleet — three routes in, what each delivers, and the limitations stated plainly.

A great deal of Indian manufacturing capacity runs on equipment that has a PLC rather than a CNC control, or has neither. Presses, moulding machines, furnaces, pretreatment lines, packing machines, special-purpose machines and the entire conventional fleet fall into this group, and they are frequently the machines nobody has ever had a timeline for.

This page describes how monitoring works for that equipment. It is deliberately vendor-neutral: what matters is whether a signal can be reached, not whose logo is on the panel.

Three ways in, in order of preference

FIRSTPLC tags or registersWhere the PLC exposes values over Modbus TCP, Modbus RTU or OPC UA, nominated tags are read directly.
SECONDExisting panel signalsWhere it does not, wired signals — drive contactor, stack light, existing counter — carry the same picture.
THIRDAdded sensorsWhere neither exists, a proximity switch, current transformer or transducer supplies the missing state.

Work top-down per machine. Each step adds either configuration effort or an installation slot, so the first route that works is usually the right one. A mixed floor typically ends up using all three, which is expected rather than a compromise.

What gets read, and what it becomes

Signal readTypical sourceWhat monitoring derives from it
Cycle runningPLC tag, or drive contactorRunning, idle and stopped states with exact durations; availability
Part or stroke completePLC counter, existing counter output, or proximity switchOutput counts, cycle time distribution, performance
Mode selectorPLC tag, or selector switch contactSeparates setup from downtime — without it both figures mislead
Alarm or fault presentPLC tag, or panel indicationDistinguishes a fault stop from an idle stop before anyone is asked
Process valuesModbus register on a controller or meterTemperature, pressure, flow, current, kWh — trended against machine state
Stop reasonOperator at the machineWhy it stopped. No signal supplies this; a person does, in two taps
Ready-made drivers versus a mapping exercise

For common device classes — energy meters, temperature controllers, drives — MachineWise carries ready-made read profiles, so a device that has been seen before is connected without repeating the register-mapping work. That covers a useful share of the equipment on a typical Indian floor.

For plant-specific PLC logic there is no shortcut, and pretending otherwise is how monitoring projects produce confidently wrong numbers. The tags that represent a cycle and a good part on your special-purpose machine exist only in your machine's program, and mapping them is a conversation between your maintenance team, your production team and ours. The method is set out in PLC signal mapping for machine monitoring.

Honest limitations

LIMIT

You get what the PLC knows

If the logic never distinguishes a good part from a cycle, monitoring cannot either until the mapping — or the logic — accounts for it.

LIMIT

No controller-level machining detail

Program names, spindle load and feed override belong to CNC controls. PLC-based equipment does not have them to give.

LIMIT

Modbus carries no meaning

A register is a number until it is mapped, and mapping errors produce plausible values rather than obvious faults. Verification against the device's own display is not optional.

LIMIT

Program changes can break a mapping

If a PLC program is modified and a tag moves, monitoring reads the old address. The mapping document belongs with the PLC backup.

What a first deployment looks like

A half-hour survey per machine establishes which of the three routes applies. Machines with a readable PLC are typically connected without stopping production; machines needing wiring take an afternoon each, scheduled around a planned stop. Both are verified by watching machine and dashboard together for a shift before anyone is asked to rely on the data.

A free pilot covers two machines for thirty days. On a PLC-heavy floor we would usually suggest one machine of each type — one readable PLC and one hardwired — because that answers the two questions that determine the shape of a full rollout.

Questions

Straight answers.

What is PLC-based machine monitoring?
Reading machine state, counts and process values from a PLC over Modbus or OPC UA, or from wired panel signals where the PLC cannot be read. It covers presses, furnaces, moulding machines, packing lines and conventional equipment.
Which PLCs are supported?
Any PLC that exposes values over Modbus RTU, Modbus TCP or OPC UA. Because the approach is protocol-based rather than brand-based, the practical question is whether your PLC can expose the tags, not whose logo is on it.
What if the PLC cannot be read at all?
Then panel signals are used instead — drive contactor, stack light, an existing counter — or a sensor is added. The resulting availability picture is the same; controller-level detail is not available either way.
Do you have ready-made drivers?
For common device classes such as energy meters, temperature controllers and drives, yes, so those connect without repeating register-mapping work. Plant-specific PLC logic always requires a mapping exercise.
Can monitoring change anything in our PLC?
No. Integration is read-only. No tag is written, no logic is modified, and nothing is downloaded to the PLC.
What happens if we modify the PLC program later?
If a mapped tag moves, monitoring will read the old address and report plausible nonsense. Keep the mapping document with the PLC backup and re-verify counts after any program change.
FREE 2-MACHINE PILOT
Live OEE on two of your machines — this week. ₹0 to start.
Software-first setup in under an hour each · your data stays on-premises · plant-specific ROI model included.