Werk #18753: UPS / PDU phases and nominal frequencies: configure upper voltage and frequency levels
| Component | Checks & agents | ||||||
| Title | UPS / PDU phases and nominal frequencies: configure upper voltage and frequency levels | ||||||
| Date | Jun 18, 2026 | ||||||
| Level | Trivial Change | ||||||
| Class | New Feature | ||||||
| Compatibility | Incompatible - Manual interaction might be required | ||||||
| Checkmk versions & editions |
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Several rulesets for UPS and PDU devices only allowed configuring lower ("below") thresholds, so over-voltage and over-frequency conditions could not be alerted on. This complements Werk #18745, which added upper voltage levels to the Voltage levels (UPS / PDU / other devices) ruleset.
The following rulesets now also offer upper levels:
- Parameters for input phases of UPSs and PDUs — new optional Upper voltage levels
- Parameters for output phases of UPSs and PDUs — new optional Upper voltage levels
- Nominal frequencies — new optional upper frequency levels
The new upper levels are optional and unset by default, so existing rules and their alerting behavior are unchanged until you configure them.
While at it, the default lower frequency levels of the Nominal frequencies ruleset were revised. The previous values (warn/crit below 45 Hz/40 Hz) were far outside any realistic operating band and effectively never triggered; they are now warn/crit below 49 Hz/48.5 Hz (a roughly ±3 % band around a 50 Hz nominal), and the pre-filled upper levels are warn/crit above 51 Hz/51.5 Hz. Frequency levels also accept fractional values now.
This changes the built-in default of the ups_in_freq check (nominal input
frequency of generic UPSs): services that rely on the default parameters — i.e.
those without an explicit Nominal frequencies rule — will evaluate against the
new, tighter thresholds after the update and may report WARN/CRIT where they
previously stayed OK. Configure a Nominal frequencies rule to keep the old
behavior. Other checks using this ruleset (for example janitza_umg) keep their
existing defaults.
The pre-filled default upper voltage levels of the input/output phase rulesets were set to warn/crit above 245 V/250 V, matching the thresholds established in SUP-28443 (devices commonly trip around 253 V).
Note: checks that have not yet been migrated to the current check API (for
example some ups_cps_*, ups_socomec_* and raritan_* phase checks) do not
yet evaluate the new upper voltage levels.