AutoTune done

If the AutoTune is done with success, a status bit ZoneData.tsProcessStatus.wStatusWord.6 for tune done is set and the PID parameters (KP, TI, TD, T1) will be calculated and the control state will change back to ready. If the control bit ZoneData.tsProcessSet.wControlWord.6 (accept AutoTune result) is TRUE, then the PID values will be copied from AutoTune result to PID values for automatic PID process with an indication ZoneData.tsProcessStatus.wStatusWord.7 (AutoTune accepted) and at the same time the automatic process will start with changing control state to PID_Process.

After accepting the AutoTune result, the control bit ZoneData.tsProcessSet.wControlWord.6 can be disabled for a fine tuning of the PID parameters.

Even if the zone data is saved as retain variable, it is recommended to save the AutoTune results and PID parameters into PLC internal flash or as a recipe file directly after AutoTune is done. Because the values can be reset by cold resetting the PLC or by downloading new PLC program. Please refer to the chapters for those two functionalities.

If AutoTune cannot be completed due to tune fault, the control state will change to Fault state with fault bit ZoneData.tsProcessStatus.wStatusWord.15 and error code TECT_TuneFault in ZoneData.tsProcessStatus.wErrors and ZoneData.tsProcessStatus.Latest_Error. To reset the fault, the enable AutoTune control bit needs to be disabled first and a warm reset with ZoneData.tsProcessSet.wControlWord.13 of process is necessary.

The AutoTune fault can happen if the temperature change between actual temperature and set point is not big enough. For such case, the user needs to wait until the machine temperature has been cooled down.