I like your work. If I ever manage to get myself a decent espresso machine, I'm going to try a PID controller mod on it.

One thing that interests me is whether you could "autotune" your PID controller using a step input (ie. turn the heater full-on), measuring the response (the lag Td and maximum slope of the resulting S-curve) and applying the method as per part D at the end of this.

Regards,

Sam.

I don't mean to nag, but that SetCalcFrequency() really needs to be changed to SetCalcPeriod(). Likewise GetCalcFreq().

IMO it's important to avoid misleading function names, particularly early in the library lifecycle, before the installed base is too large, and there's too much traction.

Apart from that it's a great library.

Haven't tested it, but it looks good.

A couple of comments -

The description of SetCalcFrequency() indicates the parameter is actually a period, not a frequency. If this is the case then the function would be better named SetCalcPeriod().

The description of Reset() is overly brief. Perhaps it is due to my unfamiliarity with PID controllers, but does this function only reset the current calculated values of measured error and any accumulated integration value? Is the value of Output affected? What about the IOLimits and Tuning parameters?

hei...i juz bought a arduino and motorshield from littlebird electronics ..i found out that the motorshield is only a pcb board.
hav anyone bought the motorshield from them? where can i get the other components like h-bridge ic n stuffs

Altronics have the H-bridge IC (if it's the L293D one).

Altronics have dealers all over AU. If you're in NZ, they dist. through Global PC in Christchurch, Papanui and Riccarton.