Innovate Motorsports LM-1 Digital Air/Fuel Ratio (Lambda) Meter - Manual (Page 9)

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7. Remote display of Lambda and/or AFR
In some applications it may be desirable to mount the LM-1 in the engine compartment or under
the dash permanently and monitor the air-fuel data remotely using a dash-mounted instrument.
The LM-1 provides two options for that application.
7.1. Analog Lambda/AFR instrument.
There are many analog lambda/AFR displays on the market. They are essentially voltmeters for a
voltage between 0 and 1 V and measure the analog voltage of a narrow band oxygen sensor.
Some are true analog instruments while others provide a LED bar. Because of the very limited
sensing range of a narrow band sensor they are essentially useless as true AFR meters. With the
LM-1, connecting these meters to the second analog output of the LM-1 allows them to be used
as true remote AFR meters, provided the LM-1 analog output is programmed to the
characteristics of the used meter. (Note: the LM-1’s Analog Out port is a mini-TRS (stereo)
connection which provides two analog outputs, plus a ground.) The LM-1's second analog output
is factory programmed to provide a linear output between 1V and 2V for an AFR of 10 to 20,
allowing a digital voltmeter to be used as the AFR display. Any other linear output range between
0 and 5V can be programmed. See chapter 9.6, 'Programming analog outputs' for details.
7.2. Special considerations when installing LM-1 permanently in the
vehicle
Do NOT install the 9V battery in the LM-1 when installing it permanently in
the vehicle.
In a typical permanent installation the LM-1 will be powered by switched 12V from the vehicle
(12V switched on when the ignition key is turned on) while its power switch is permanently on.
Because the LM-1 automatically switches to internal battery power when it does not detect 12V,
the internal battery would drain quickly while the vehicle is parked. To avoid this, do not install the
9V battery. The LM-1 will function correctly without it and will be able to record as usual. To
download recorded data, follow the alternate steps described in chapter 9.
It is NOT a good idea to connect the LM-1 permanently to 12V and switch it on before the vehicle
is started. Depending on the climate and the senor position in the exhaust, condensation water
can form in the exhaust pipes. This condensation water could then be blown by the exhaust
stream against the hot sensor when the car is started. The resulting heat shock can permanently
damage the sensor.
To protect the LM-1 when installed permanently it is a good idea to power the LM-1 only after
the car is started. The starter motor in some vehicles can create voltage spikes of over 100V
that have the potential to do damage. Although rare, this is a real possibility and the LM-1
contains protection circuitry to guard against it. A relay connected as shown below insures that
the LM-1 is disconnected while cranking. This reduces further drain on the car battery by the
sensor heater and protects the LM-1 against abnormally large voltage spikes.