oxidecomputer / oxidecomputer/hubris

Sidecar fan current scaling incorrect

Open
#2,202 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Dominant language
Rust
Stars
3.6k
Forks
239
Avg merge
1d 12h
Merged PRs (30d)
23

Description

Not sure if this is a hubris or humility issue, but the ADM1272 current measurements on the fans for Sidecar have the incorrect scaling. They are reporting a current that is 2x the actual current.

From humility sensors:

NAME                 KIND                  VALUE UNPWR   ERR MSSNG UNAVL TMOUT
V54_FAN1             current                5.97     0     0     0     0     0

Actual current is 3.0A on an external electronic load. The current sense resistor on the fan HSCs is 2 milliohms but the main HSC is 1 milliohm.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start from the humility sensors entry point and locate the Sidecar ADM1272 fan current-scaling configuration. Compare the 2 milliohm fan HSC sense resistor with the 1 milliohm main HSC value; done means the reported fan current matches the external electronic-load measurement.

Written by the indexing model from the issue text.

Assessment

Domain
embedded-iot
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
48/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.