Electronic control apparatus and control characteristic adjustment method for the same having a label resistor for calibrating a device-variability variation

An electronic control apparatus comprising:

• a microprocessor which performs drive control for an electric load group in accordance with an operation state of an input sensor group and a content of a program memory, in which a specific sensor of the input sensor group has a label resistor for calibrating a device-variability variation in a detection characteristic of the specific sensor, or a specific load of the electric load group has a label resistor for calibrating a device-variability variation in an output characteristic of the specific load, wherein
• the microprocessor is further connected to a RAM memory for arithmetic processing, a non-volatile data memory which is a certain area of the program memory or is separately provided, and an analog to digital (AD) converter, and operates in cooperation therewith,
• the program memory or the data memory has stored therein, in a predetermined data form, standard characteristic data which is standard detection characteristic data of the specific sensor or standard output characteristic data of the specific load, which is average characteristic data of experimental data based on a plurality of samples thereof,
• the detection characteristic or the output characteristic has a monotonic increase property or a monotonic decrease property in which a second differential value thereof does not reverse between positive and negative, and is approximated by a polygonal line characteristic,
• the program memory or the data memory further has stored therein interpolation information for compensating error between the standard characteristic data approximated by the polygonal line characteristic and actual standard characteristic data,
• the program memory includes a control program functioning as label resistor reading conversion means,
• the label resistor reading conversion means calculates the resistance value of the label resistor by referring to the resistance value of a series resistor connected in series to the label resistor, the both-end voltage of the label resistor, and a control voltage which is a voltage applied to a series circuit, calculates a correction constant for correcting the device-variability variation in the detection characteristic of the specific sensor or the output characteristic of the specific load, based on the calculated resistance value, and stores the correction constant in the data memory or the RAM memory,
• the correction constant is a pair of adjustment factors, a pair of adjustment addition values, or a complex combination of an adjustment factor and an adjustment addition value for specifying individual characteristic data which is individual detection characteristic data of the specific sensor or individual output characteristic data of the specific load, based on the standard characteristic data,
• the interpolation information is applied for, based on the individual characteristic data obtained by approximating one polygonal line composed of a pair of segments by one synthesized line, restoring the synthesized line to the one polygonal line,
• the adjustment factor is a correction constant to be multiplied by the standard characteristic data, thereby obtaining the individual characteristic data, the adjustment factor being an adjustment coefficient which is a relative ratio between the individual characteristic data and the standard characteristic data at a predetermined adjustment comparison point, or being a gradient coefficient which is a relative ratio with respect to change rate between the individual characteristic data and the standard characteristic data at a predetermined adjustment comparison point,
• the adjustment addition value is a correction constant to be algebraically added to the standard characteristic data, thereby obtaining the individual characteristic data, the adjustment addition value being a bias adjustment value which is a relative deviation between the individual characteristic data and the standard characteristic data at a predetermined adjustment comparison point, or being a gradient adjustment value which is a relative deviation with respect to change rate between the individual characteristic data and the standard characteristic data at a predetermined adjustment comparison point,
• the label resistor reading conversion means is executed at the start of operation when a power supply switch is turned on, or when the specific sensor or the specific load is replaced upon maintenance, to identify what combination the correction constant includes, of the adjustment coefficient, the gradient coefficient, the bias adjustment value, and the gradient adjustment value, and restore and generate the individual characteristic data by combining the identified correction constant, the standard characteristic data of the specific sensor or the specific load, and the interpolation information, and
• the microprocessor performs drive control for the electric load group by referring to the generated individual detection characteristic data, or performs drive control for the specific load by referring to the generated individual output characteristic data.