Do PID Process

PID process is an automatic process with a PID controller which outputs control variables according to actual temperature as feedback. To start PID process, the valid PID parameters (KP, TI, TD, T1) are necessary. Internally, it check the following conditions for valid parameters:

• KP > 0,
• TI >= 0,
• (TD>0 AND T1>0) OR (TD=0)

If the values are not valid, then the PID process cannot be started with a warning: NoPIDProcess.

The PID parameters can be accepted from AutoTune result, can be set during fine tuning or can even be set manually without AutoTune process.

If the user has already write the PID parameters into internal flash or a recipe file, then they can be read back from flash or a recipe file.

For PID process, two set points are possible. Normal set point for production and standby set point for energy saving. The switch between both is done with a control bit ZoneData.tsProcessSet.wControlWord.4 (enable standby set point). The currently used set point will be transferred to active set point.