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Zt-3 Linear Wideband Output
Engine Management Systems Setup Instructions

The following instructions detail setting up the Zt-3 linear wideband output for use with after market engine management systems. System requirements vary with some needing a 0-1 volt signal while others require a 0-5 volt signal.  AFR values at these voltages also vary from 8, 9.6 or 10 AFR at 0 volts to 19.6, 20, or 22 AFR at 1 volt or 5 volts. These instructions provide the best method for getting the most accurate AFR/Lambda values to your engine management system (EMS).

EMS Setup for 0 - 5 volt ranges

  1. Enter the value required by your EMS in the first box (for 0 volts).
  2. Enter the value required for 5 volts in the last box.
  3. Press the "Auto Fill" button. This will automatically set the other values using a linear distribution. Press OK
  4. Connect the Zt-3 linear wideband output wire (white color) to your EMS input. The black Zt-3 ground wire should be grounded at the same location as your EMS.

NOTE: Any values outside of the range of the Zt-3 range of 9.6 to 21 will not be saved and will need to be re-entered to make changes.  The slope of the Zt-3 linear wideband output is still correct matching the values originally entered until changes are made.


EMS Setup for 0 - 1 volt ranges
These instructions provide the best way to connect the Zt-3 linear wideband output to a system expecting a 0-1 volt AFR/Lambda signal. In order to get the most accuracy and highest resolution the Zt-3 output will be setup for a 0-5 volt range. Next a voltage divider will be used to scale the 0-5 volt signal down to a 0-1 volt signal. The scaling process works independently of the range of the AFR or Lambda values you require.

  1. Enter the value required by your EMS in the first box. For instance enter 8 in the first box for 0 volts.
  2. Enter the value required for 1 volts in the 5 volts box. For instance enter 22 in the last box for 5 volts.
  3. Press the "Auto Fill" button. This will automatically set the other values using a linear distribution.  Press OK.
    * As mentioned above - returning to edit these values will not save any values outside of the 9.6 to 21 AFR range of the Zt-3.  You will need to entered them again if making changes.
  4. Connect the Zt-3 and the EMS together using the following voltage divider diagram.
    The 0-5 signal will be reduced to a 0 - 1 volt signal.
    3.92k Ohm and 1k Ohm resistors are available from Zeitronix and most electronics stores.
    (If purchased from Zeitronix the fatter sized of the two resistors is the 3.92 KOhm resistor.)