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| author |   Christopher Peplin <chris.peplin@rhubarbtech.com> | 2014-03-26 13:57:36 -0400 |
|---|---|---|
| committer | Christopher Peplin <chris.peplin@rhubarbtech.com> | 2014-03-26 13:57:36 -0400 |
| commit | ab912b63e81209637f77f2e3eba23c5e75309dcb (patch) | |
| tree | ffb7ed91bd0292097bb201d61d3505c371be4ad9 | |
| parent | f1c1af529c32284c6b81a6ba4fcada464ce4401f (diff) | |
Clarify how diagnostic requests are identified, updated and cancelled.
| -rw-r--r-- | README.md | 24 |
1 files changed, 19 insertions, 5 deletions
@@ -97,7 +97,8 @@ with this command format: in the VI for longer. **frequency** - (optional, defaults to 0) The frequency in Hz to send this - request. To send a single request, set this to 0 or leave it out. + request. To send a single non-recurring request, set this to 0 or leave it + out. **decoded_type** - (optional, defaults to "obd2" if the request is a recognized OBD-II mode 1 request, otherwise "none") If specified, the valid values are @@ -105,10 +106,23 @@ OBD-II mode 1 request, otherwise "none") If specified, the valid values are OBD-II specification and returned in the `value` field. Set this to `none` to manually override the OBD-II decoding feature for a known PID. -The `bus+id+mode+pid` key is unique, so if you send a create request with that -key twice, it'll overwrite the existing one (i.e. it will change the frequency, -the only other parameter). To cancel a recurring request, send this command with -the frequency set to 0. +A diagnostic request's `bus`, `id`, `mode` and `pid` (or lack of a `pid`) +combine to create a unique key to identify a recurring request. This means that +you cannot simultaneosly have recurring requests at 2Hz and 5Hz for the same PID +from the same ID. + +If you send a new `diagnostic_request` command with a `bus + id + mode + pid` +key matching an existing recurring request, it will update it with whatever +other parameters you've provided (e.g. it will change the frequency if you +specify one). + +To cancel a recurring request, send a `diagnostic_request` command with the +matching request information (i.e. the `bus`, `id`, `mode` and `pid`) but a +frequency of 0. + +Non-recurring requests may have the same `bus+id+mode(+pid)` key as a recurring +request, and they will co-exist without issue. As soon as a non-recurring +request is either completed or times out, it is removed from the active list. If you're just requesting a PID, you can use this minimal field set for the `request` object: |