Downtime logging that operators actually use

Most downtime sheets fail the same way. They sit in an office, get filled at the end of the shift from memory, and say “machine breakdown, 2 hours” against half the entries. Nobody can act on that. The data gets better when the operator is asked at the machine, at the moment of the stop, and the answer takes one tap.

Let the machine say when it stopped

Do not ask the operator when a stop began or ended. The machine knows. A stop can be detected from a PLC run bit, a cycle counter that has not moved for a set time, a stack light signal, or a current sensor on the motor. On a Modbus or MQTT feed, a rule such as “no cycle for three times the normal cycle time” works for many machines. A fixed threshold such as five minutes suits others.

Short stops need a decision. Many plants log only stops above a minimum length, say two to five minutes, and count the smaller ones as speed loss. Pick the limit with the production head, write it down, and apply it the same way on every machine.

One tap, next to the machine

When a stop passes the threshold, a tablet or phone mounted at the machine shows a screen with the reason list. The operator taps one. That is the whole task.

• Keep the list to about eight reasons, large enough to hit with a gloved finger.
• Group them the way maintenance and production think: breakdown, changeover, material wait, quality check, no operator, planned stop.
• Put the most frequent at the top, and let a supervisor add a reason with a name, not free typing at the machine.
• Allow a later change, so a stop first tapped as “other” can be fixed after the cause is known.

If the stop ends before anyone taps, keep the record with the reason empty and show it to the supervisor. An unanswered stop is itself useful data.

Let it work through a bad network

The app should store taps on the device and sync when Wi-Fi returns. A shop floor has dead spots, and an app that waits for the cloud will lose entries and trust together.

Reports people read

The supervisor needs a shift report within minutes of the shift ending: downtime by reason, by machine, and the top three stops by length. Add the unanswered stops. A single page, with a bar for each reason, gets read. A twenty-column export does not.

What it does not fix

A logger shows where time goes. It does not say why the machine failed. Reason codes are only as honest as the culture around them, and if an operator is blamed for every “no operator” entry, the entries will change. Agree the purpose first: the data is for fixing machines and flow, not for scoring people.

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