MembersPage/WolfTm/InputPullupAndEgtAmplifier (2018-06-13 14:04:02)

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Summary:

The 100C/V (0-11V) output of the [EGT amplifier] can be used with some care, if the ECU was not ordered with the sufficient number of EGT inputs or analog inputs without pullup. See "GOOD granularity" below.


When ECU is purchased with 1,2 or more (4 or 6 is sometimes requested, some logger was ordered and delivered with 8 EGT inputs),

Confirmed:


Unfortunately NO input with no pullup resistor in this ECU.

Rough granularity/resolution

The EGT amplifier (internal voltage divider for convenience =) 233C/V (= also called "5V output") has an output protection equivalent to

Best to use input with no pullup.


Achieving GOOD granularity, using the 100C/V (= also called 0-11V) output and 2 resistor voltage divider:

Connecting the analog input (with internal 2k7 pullup) via/to:

This acts like 0-11V => 2.5 - 5V output divider

Needless to say: take care when using the 100C/V output, do NOT short to GND or 12V (only connect to the 1 end of the 5.3k resistor, use heatshrink, do not leave it uninsulated).


Orig report:

Engine off, ambient sensor temp (~20C)

Hint: The output is almost certainly connected to an input with pullup (possibly strong pullup).

Sensor connection (seems good):

EGT sensor is K type yellow-red wires:

  • yellow = green (plus wire) to board GND
  • red = white (minus wire) to the board cathode on corner