AN2446

Customization: software and hardware modifications

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Customization: software and hardware modifications

The STEVAL-IHT002V1 evaluation board can be fully adapted to the compressor the user

intends to test. Different parameters such as the temperature offset or the dead-time period

can be changed. Only a few easy software or hardware modifications are necessary.

5.1

Cabinet temperature offset

There is only one variable for the cabinet temperature offset. Therefore the positive offset is

equal to the negative one.

The constant to be modified is named Offset, defined in the main() routine, where the

defines are declared. The value is expressed in bits.

The range between 0°C and 5°C corresponds to 50 bits. So 1 °C is approximately 10 bits.

Default value: 15 (possible range: 0 to 255)

5.2

START winding duration

When the compressor is turned on, both the RUN winding and the START winding are

supplied. After a while, the START winding is no longer supplied.

The time the START winding is supplied can be changed. The constant to be modified is

named START_Period, defined in the main() routine, where the defines are declared.

The value is expressed in periods.

A value of 10 means therefore 10 periods, equal to 200 milliseconds (mains frequency

50 Hz).

Default value: 25 (possible range: 0 to 255).

5.3

Stall rotor control duration

The stall rotor control starts as soon as the compressor is turned on and lasts a certain time.

This time can be changed. The constant to be modified is named Window_Period, defined

in the main() routine, where the defines are declared. The value is expressed in tens of

milliseconds.

A value of 1000 means 10000 milliseconds, or 10 seconds. It is suggested not to exceed a

value of 10000.

Default value: 500 (possible range: 0 to 65535, in any case, do not exceed 10000).

5.4

Dead-time duration

The dead-time is set once the compressor is turned off or when a stall rotor condition has

been detected. During this time, the compressor cannot be turned on, even if the cabinet

temperature rises up over the threshold set by the user.

There is one constant only. Therefore the dead-time set after the compressor turn off and

the dead-time set after a stall rotor detection are the same.