Process Set Values / Parameters

TECT_PROCESS_SET_TYPE structure contains all the process related parameters.

This structure contains process set parameters of the zone data. User can define all parameters which are related to the process, i.e. parameters which are set as per process properties. These parameters will be changed continuously as per process requirement, e.g. in structure Control Word.

PID Set Point, Control Word, High Temp, Low Temp settings comes under this structure.

Control Word (wControlWord)

The Control Word setting will define the working of the machine / process. The user needs to set the Control Word bits per requirements .These settings will decide the working philosophy of the machine. The user also needs to decide which parameters he want to set permanently and which parameter he wants to change frequently.

E.g. Heat_en and Cool_en can be set permanently and Enable can be used to turn on and off the temperature zone.

  • Enable (Bit 0):

    When this is TRUE, it will enable the process of temperature control. If this bit is FALSE, the complete process will stop and wait for next on command in Ready State.

  • Heat_en (Bit 1):

    It will enable the zone as heat zone and the heating process starts when the duty cycle is greater than 0.

  • Cool_en (Bit 2):

    It will enable the zone as a cooling zone and the cooling process starts when duty cycle is greater than 0.

  • Manual_en (Bit 3):

    This is the highest priority mode. When this is TRUE, all the other modes are disabled and the manual control becomes active.

  • Standby_en (Bit 4):

    When this bit is TRUE, the Standby set point becomes an active set point for the process.

  • Tune_en (Bit 5):

    It will enable the auto tune process for the system using a tune step. It will start the tuning of the zone and calculate the optimal KP, TI, TD and T1 values.

  • Accept_auto_tune (Bit 6):

    If the TRUE system will accept the calculated auto tune parameters.

  • Co_Output (Bit 7):

    When this bit is TRUE, it will consider coordinated output for the particular group. It avoids switching on all zones simultaneously, thus avoiding a voltage drop in the power supply system. At the same time, it compensates the error between digital outputs and duty cycle due to CPU task cycle.

  • Control Optimization (Bit 10, Bit 9):

    A combination of these two bits decide the working principle for the PID control.

    • 00 – APERIODIC:
    • 01 – OVERSHOOT:
    • 10 – DEADTIME COMPENSATION:
    • 11 – Default: APERIODIC

  • Warm_Reset (Bit 13):

    When this bit is TRUE, it will reset the all alarms and process in the zone, but it will retain the auto tune status.

  • En_3Phase_Monitor (Bit 14):

    When this bit is true, 3 phase current monitoring is enabled. If false, then single phase current monitoring is enabled.

  • Cold_Reset (Bit 15):

    When this bit is TRUE, it will reset everything in the control process and the Status Word of the process will become zero. Auto tune has be carried out once again for the zone, as auto tune values have been reseted by cold reset.

PWM output in Manual mode. The Manual duty cycle needs to be set by the user when the manual mode (i.e. control word bit 3) is enabled for the process.

In the Manual mode the Manual duty cycle is passed on as a process duty cycle. That means the process duty cycle is not dependent on the set point and actual temperature. If not monitored properly, this can lead to accident.

Set Point (rSetPoint):

This is a secondary process set point which has to be set by the user. This value is considered for the process when Standby_en (control word bit 4) is TRUE.

Standby set point: (rStandBy_SetPoint):

This is a secondary process set point which has to be set by the user, this value is considered for the process when Standby_en (control word bit 4) is TRUE

High Temperature (rHigh_Temp):

The High Temperature value has to be set by the user as per process requirement. If the actual temperature becomes more than a High temperature, then the heat output is disabled and an alarm is generated.

Low Temperature (rLow_Temp):

The Low Temperature value has to be set by the user as per process requirement. If the actual temperature becomes less than Low temperature, cool output is disabled and an alarm is generated.

High Deviation (rHigh_Deviation):

If a difference between the actual value and the set value is more than the High Deviation, then an alarm is generated.

Low Deviation (rLow_Deviation):

If a difference between the actual value and the set value is less than Low Deviation, then an alarm is generated.