ST STEVAL-IHT001V1, Руководство пользователя

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UM0277 Getting started
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Figure 10. Temperature control tab
3.5.2 Timing control
The Timing Control tab ( Figure 11 ) controls the gate current width for the TRIACs, the delay
to switch ON the TRIACs Q1 (for compressor), the ZVS delay, the delay to activate defrost
and the defrost duration. Note that the initial parameters are given in
Appendix F . These
parameters are sent and received by clicking on “Set” or “Get” buttons, respectively.
Figure 11. Timing control tab
The ZVS delay is the delay between the AC mains zero voltage and the detection of this
zero voltage by MCU in order to synchronize the MCU orders with the AC mains voltage.
The MCU uses Zero Voltage Crossing (ZVC) events to synchronize the TRIACs' gate
current pulses. The LINE voltage is connected to the input pin through two resistors (R7 and
R8). An interruption will then occur at each ZVC event. As soon as the ZVC is detected, the
AUTO-RELOAD Timer is started and a routine is launched to define the PORT A
configuration. The required time introduces then a delay from the ZVS. The maximum delay