TCI v12

A pickup (aka: VR, Variable Reluctor, Reluctor, Trigger coil, Magnet) is a sensor with one signal and one ground line.
It consist of a wire coiled around a magnet. When a ferrous object passes by the magnet, the magnetic field is modified and a voltage pulse is generated in the coil, resulting in a sine wave.

– Inductive pickup MUST gives 1 signal per crank revolution.
– Pickup MUST puts out 3 to 30Vac

– This TCI works with ONE pulse per rev. 1 pickup and 1 reluctor (the metal strip on the flywheel) [“A” or “B” below].
– This TCI works with 2 pickups and 2 bars [E,F].
– This TCI DOES NOT work with 1 pickup and a multi-pulse pickup (ie 2 reluctors on the flywheel) [C,D].
– This TCI DOES NOT work with 1 pickup and a missing tooth flywheel [G].

“Pickup Position” is the number of degrees between the very first pulse from the pickup and TDC

To be able to provide the largest advance timing (Example 36° @ 4500rpm) the pickup MUST send a trigger signal BEFORE the piston reaches 36° before top dead center (BTDC).
The “Pickup Position” on the Yam XT600 is 50°.
Many Yamahas have a “Pickup Position” of 72 degrees.

This “Pickup Position” is dependent on:
– Where the pickup is mechanically located with respect to TDC?
– Where is the flywheel’s bar located?
– How long is the flywheel’s bar?

“Pickup Position” is always superior or equal to “Max Advance”.
“Max Advance” = “Base Advance” + “Flywheel’s bar Length”

“Base Advance” value is often written is the User Manuel.
Length of the flywheel’s bar can be measured this way.

You may measure the “Pickup Position” using a protractor or with a caliper and some math.

When the bar/magnet on the flywheel passes in front of the pickup, the pickup generates two pulses of OPPOSITE polarity.

A pickup has 2 wires. If you ground wire number 1, wire number 2 will put out a Positive pulse first when the rising edge comes, then a Negative pulse when the falling edge leaves. I call it PN.
If you ground wire number 2, wire number 1 will put out a Negative pulse first, then a Positive pulse. I call it NP.

Pickup Polarity MUST be Positive then Negative to work with this TCI.

Check the polarity of the pickup (Negative going then Positive/(I call it NP) or the opposite PN: Positive going then Negative) with a Needle galvanometer (in milliAmp position) while kicking.

If the polarity is Negative then Positive(NP) then the leads are backward, just swap the wires to change the pickup polarity !

Watchout! If the pickup is internaly grounded and output ONLY one wire, you won’t be able to change the polarity.
So if the polarity is NP (Negative first) then you CANNOT use this ignition!

Optional
– Points, reluctors, Hall sensors, optical sensors can also be used as long as they give only 1 pulse per revolution. They may need an additional pullup resistor.

– 3 wires digital Hall effect sensors need an external pull-up resistor. The default voltage output is equal to Vcc (+5v to 24v). When a magnet passes in front of the sensor, the output voltage goes low and the ignition will detect the RISING edge meaning the trigger moment will be when the magnet LEAVE the sensor.

Models : Hamlin 55100, Allegro A1101-A1104, Allegro old 3141-3144, Honeywell 1GT101DC, SS495, SS49E etc…
Pullup resistor: 370ohm (270 to 1200ohm)

600rpm: 6000rpm:

Video

For diagnostic or tuning purpose, it’s possible to live view RPM and Timing in degrees BTDC on a remote PC connected through Wifi: Video
Because of the impact on TCI performance, please use it for debug only and disable this function when you are done with it!

Optional

An output for connecting a digital Tachometer is available.
Output signal is a 0 to +12volts square signal:

– For test only. Useful to test the ignition box, coil, sparkplug(s).
If “Auto-Spark” mode is set to 1,2,3 or4 during Setup then once the TCI is powered on, it automatically drives the coil at 300 to 10,000RPM without the need of any pickup.
Pickup can be disconnected.
0 = disable.

– Only for testing purpose. This function will fire a spark as soon as a pickup pulse is detected, bypassing the advance timing.
/!\ Don’t use the function on a running engine otherwise the spark will append way too soon and could damage the piston !!
But along with points and mechanical advance system, TCI in Bypass Mode is acting as a simple Transistorized Ignition.

– If the box is started in RUN Mode and you have selected Curve N°1: The Led flashes 1 time then stays Off.
The led blinks in time when a pickup signal is detected.

– If the box is started in RUN Mode and you have selected Curve N°2: The Led flashes 2 times then stays Off.
The led blinks in time when a pickup signal is detected.

– If the box starts in SETUP Mode : Led blinks 5 times fast then flashes once every 5 seconds.
The led flashes briefly when data arrives through WIFI.

• Version v12r0c0:
  • [Hard] Replace wires by connector
  • [Hard] Add a VR conditioner for noisy environment
  • [Hard] Add Hall Effect Sensor input
  • [Soft] 2 Curves available
  • [Soft] HTML form changed

• Version v12r3c0:
  • [Soft] Wifi stability improved