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Condition Monitoring Alarm Limits Register Worksheet

Alarm limits tend to live in the heads of analysts or buried in vendor software settings. This register puts every limit, baseline and owner on one sheet, so changes are visible and the team knows who responds when a value crosses.

Download:

Asset	Parameter	Technique	Unit	Baseline	Alert limit	Alarm limit	Latest value	Percent of alarm	Responder
								95.8%
								18%
								92.5%
								89.5%
								87.4%

Highest percent of alarm

95.8%

Parameters registered

This register assumes high values are bad. For parameters where a low value is bad, such as oil film thickness or flow, record the limits inversely and treat the percent column accordingly. Review limits after every major repair or load change.

Alarm limits that feed your ERP

Optional review of how alarm crossings could create maintenance notifications automatically.

Optional. The tool and every export work without this. No spam.

How to use the register

List each monitored parameter once, with its technique, unit and baseline taken when the asset was healthy. Set alert and alarm limits from a standard, the manufacturer or statistics of your own history. Update the latest value after each survey and the sheet shows how close each parameter is to its alarm. Assign a responder so a crossing is never ownerless. Export to Excel for review meetings and audits.

Setting alert and alarm levels

There are three common routes. First, use published severity zones such as the ISO 20816 families for vibration. Second, use the equipment manufacturer values. Third, use statistics: for example the baseline plus two standard deviations for alert and plus three for alarm once you have enough data. Mixing approaches is fine as long as the source of each limit is noted, so you can justify changes later.

Alert means plan an inspection, alarm means act now
Review limits after repairs, speed or load changes
Keep a rate-of-change rule in addition to absolute values

Using percent of alarm

Percent of alarm is the latest value divided by the alarm limit. It lets you rank very different parameters on one scale. Values over 100% are in alarm, and those above the alert level but below alarm sit in the amber zone. Sort the exported file by this column before the weekly reliability meeting to decide which assets to discuss first.

Common mistakes

Frequent problems are copying limits between unlike machines, leaving baselines out of date after an overhaul, too many alarms that train people to ignore them, and alarms with no response plan. Aim for few, meaningful alarms and a clear next step for each.

Frequently Asked Questions

Can I use this for online monitoring systems?

Yes. Use it as the master record of what each system should alarm on, then compare against the configuration in the software. It is especially useful when limits have been changed over time by different people.

How many parameters should I register?

Start with the critical assets and the two or three parameters that best reflect their main failure modes. A short register that is kept current beats a long one that nobody updates.

What if a parameter has only a low limit?

Enter the limits inversely or rename the columns in the Excel export. The percent formula assumes higher is worse, so for low-is-bad parameters calculate the margin separately.

Who should approve limit changes?

Usually the reliability engineer with the asset owner. Record the date and reason in the note field of your exported copy to keep an audit trail.

Netray can help connect your limits to live data so crossings create notifications in your ERP maintenance module automatically.

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