How to Clamp a Voltage Signal Negatively

If for any reason you want to clamp a signal in the negative direction, in other words, keep the fuel signal from going BELOW a value you can do so with the Unichip. A typical application is on an engine with a MAF sensor that works from a high voltage at idle down to a low voltage at maximum power or on a after-market turbo vehicle where you want to prevent the MAF value to drop below a certain value to improve idling.

Tip! Only the TPS output can have a negative clamp so you have to use the TPS in and TPS outpin to control whatever signal you want to clamp negatively. If you put a value smaller than 2.5 volts in the TPS clamp it will clamp negative. Any value bigger than 2.5 volts will clamp positive like normal.

Only the TPS output can have a negative clamp so you have to use the TPS in and TPS out pin to control the fuel (or whatever signal you want to clamp negatively). If you put a value smaller than 2.5 volts in the TPS clamp it will clamp negative. Any value bigger than 2.5 volts will clamp positive like normal.

As an example if you put a value of 0.35 volts in the TPS clamp map, enable the clamp and download, the Unichip will not allow the TPS output to go any lower than 0.35 volts. If you ever need a positive and negative clamp you will have to put the signal in on the TPS in, put the TPS out on fuel in and put the fuel out to the ECU. In this way you can clamp the positive value on the fuel map and clamp the negative value on the TPS map.