What does the engine-hours validator do?
A machine can report its engine hours three ways: the hour meter on the dash, the engine-hours value the engine sends on CAN, and the engine-on time the tracker logs from its ignition input. The validator compares the three for one period, per machine, and tells you which input the tracker should read from now on.
Why do the sources differ?
- An ACC or key-on wire counts time with the key on and the engine off.
- Power cuts, a sleeping device or a loose input lose engine-on time.
- Some hour meters run on key-on, others only with oil pressure or under load.
- A replaced or faulty meter stops matching the engine.
Inputs you need
| Input | Where to find it | Tip |
|---|---|---|
| Hour meter readings | The dash of the machine | Photograph them with the date. |
| CAN engine hours | The tracker or platform, if it reads CAN | Leave empty if the machine does not send them. |
| Wire hours | The engine-on report of the tracker for the period | Same dates as the meter readings. |
| Tolerance | Your maintenance practice | 2 % is a typical starting point. |
How it is calculated
Each source gives hours for the period. The drift of a source is its difference from the reference, as a share of the reference. When the wire and the second source agree with each other but not with the reference, the reference is the odd one out. A meter that did not move while the engine ran is set aside and CAN becomes the reference.
Worked example
Loader 03: the meter moved from 2,870 to 3,038 h, so 168 h. The tracker logged 191.5 h on its ignition wire. Drift = (191.5 - 168) / 168 = +14.0 %. The wire counts more than the engine ran, which points to an ACC or key-on wire. Factor = 168 / 191.5 = 0.8773. At 180 h a month the counter drifts 25.2 h a month, so with a 10 h limit it would need a reset about every 12 days. Moving the wire is the better fix.
Reading the results
- Read CAN engine hours: the engine's own count agrees with your reference, so the tracker should read it.
- Keep the ignition wire: the wire agrees within your tolerance.
- Move to a run-only signal: the wire counts key-on time. Use IGN, the alternator D+ terminal or an oil-pressure switch, after checking the wiring diagram.
- Check wiring and power: the wire loses time. Look at power cuts and the input connection first.
Assumptions and limits
One period per machine is a sample, not a law: repeat the check after a change. The factor corrects one period with the same cause. It does not fix the cause. The tool checks sources of engine hours. It does not price machine hours or check invoices.