Thermocouple
The connector indicated as TERM on Gyra DS model devices corresponds to an input for type "K" thermocouples. The system is calibrated to perform the correction and linearization of this type of thermocouples.
Type "K"
Type "K" thermocouples are the most common in motorsport environments. They are primarily used for measuring exhaust temperature, which is why they are usually presented with an exposed junction to respond more quickly to temperature changes and have low thermal inertia. Although non-exposed thermocouples are also very common.
Another typical use is measuring cylinder head temperatures. These special thermocouples are available on the market in washer format, to be mounted under the spark plugs.
It is recommended to use insulated thermocouples, i.e., those that do not have electrical continuity between the two thermocouple wires and the mechanical body of the thermocouple.
Thermocouple Wire Colors
Type "K" thermocouples have polarity, meaning that the connection direction must be respected according to the (+) and (-) poles. The polarity is indicated by the color of the thermocouple wires, but these colors are standardized according to different norms. Depending on the thermocouple supplier, the wire colors may change.
Some of the most common standards are these:
IMPORTANT
If the temperature indicated in the software works in reverse, i.e., decreases as it heats up, it's because the connection polarity is inverted. Reverse the wire colors and it will be corrected.
If the indicated temperature does not correspond to the actual temperature, it is very likely that you are using another type of thermocouple, such as "J" or "T". The calibration included in the software is adjusted exclusively for type "K" thermocouples.
Thermocouple Input Pinout
| Number | Function | Range |
|---|---|---|
| 1 | Signal(+) | Thermocouple + Signal |
| 2 | Signal(-) | Thermocouple - Signal |
| 3 | GND | Auxiliary ground |
| 4 | +5V | Auxiliary +5V |
| 5 | GND | Auxiliary ground |
The auxiliary grounds and +5V voltage are for general purpose. They can be used to power other sensors. Please do not exceed 100mA consumption to avoid affecting the equipment's calibration performance.