The Emerald "FPs" data block

Rough and ready notes on the "FPs" Emerald data block. Please let me know if you have any further information.

Sent at ~ 16 Hz, continuously when ignition is on.

Characters (spaces are for readability only; they are not in the data) Meaning
SOH (ASCII 0x01) Start of header.
FPs Identifies the type of block
RS (ASCII 0x1E) 0 rrrr Record 0
rrrr: engine revs (in rpm), in hex.
RS 1 ss.. ss: speed site (coarse measure of rpm), in hex. 0-31.

Last two digits are not ignition correction because they change, even when the engine is warm.
RS 2 tttt tttt: raw throttle position, in hex
RS 3 llxx ll: load site (coarse measure of throttle), in hex. 0-15.

xx: Something related to throttle. Seems to exagerate changes in throttle.
RS 4 jjtt jj: injection.

tt: throttle position, as a percentage, in hex. 0-100. Much lower resolution than 2tttt, obviously I suppose.
RS 5 ..ii First two digits are inversely related to throttle.

ii: 2 * ignition (e.g. if ignition = 29.5 deg. then ii = 29 * 2 = 59 = 0x3B.
RS 6 .... Probably xxyy.
xx: low resolution, seems to only be 8 steps. Seems to track throttle, almost exactly.

Last two digits are always? 00.
RS 7 .... Always? 0000.
EOT (ASCII 0x04) End of transmission.
fpE Indicates the end of this block.

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This page is It was first published on Thursday 2 December, 2004 and last updated on Thursday 2 December, 2004.