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Originally posted by 69767C6D707E727A6D1F0 link=1263349474/18#18 date=1263895634
That was quick Mal P parameter kicks in and and turns off element slowing temp rise, 125C I steam at 140C just by watching the PID readout, I guess Im just set in my ways, cant teach an old dog new tricks mate.
That sounds a bit odd too mate but I guess if youve been happy with boiler temperature management to date, theres no need to go changing things around at this late stage. What ever works for you, works; and thats the main thing....
That was quick Mal
P parameter kicks in and and turns off element slowing temp rise, 125C I steam at 140C just by watching the PID readout, I guess Im just set in my ways, cant teach an old dog new tricks mate.
Originally posted by 223D37263B35393126540 link=1263349474/16#16 date=1263894288
Raising the set point to 150 degrees didnt work to well, poor little PID had to try and make sense of paramaters adjusted to suit brew temp and set point at steam temp.
Hmmm....
That sounds a bit strange mate. Raising the Setpoint shouldnt make any appreciable difference to the behaviour of the controller - It is after all, the same physical process variable, just a higher temperature. I wouldnt have gone as high as 150C though, 125C should have been plenty high enough.....
Raising the set point to 150 degrees didnt work to well, poor little PID had to try and make sense of paramaters adjusted to suit brew temp and set point at steam temp.
My OT2 is configured as the shot timer I use it as my PI reference, I dont really feel like wiring in the SSR for steam control and reconfiguring the pid, I could just up the PID temp for steam and see how that goes.
Cant hurt and Im speaking from my own personal experience with a very similarly specd machine. Sure, the t/stat will switch on once the boiler water temperature falls below its (the t/stat) particular dead-band. Compared to a properly configured PID Controller though, this will be up to 10-15C below the point at which the PID Controller will operate....
Hi Mal
I personally cant see the advantage in steam control if I start steaming before the steam thermostat shuts off the element will remain on throughout it cant keep up therefore it wont turn off on me I get full pressure throughout.
I like the shot timer and wouldnt give it up for steam control.
Just my opinion though.
A Relay Output is of no use at all for small boiler control. You need a Pulsed DC Output designed to interface with a Solid State Relay (SSR). Will last forever and provide a higher level of response....
My PID does not have steam control so I have no experience of this function but the way I look at it is once I start steaming the element cant maintain the temperature therefore it wont switch off on me.
Why do what I did vr....
Takes about 2 seconds to up the Setpoint to 125C (for steam) and when youre finished, another 2 seconds to reset back to Brew Temp.
Youll notice a hell of a difference with the Steam Capacity mate, since the PID will hold the temperature much tighter than the original t/stat and as a result, the second that the boiler temperature dips below the Setpoint the element is switched On, not after a dip of 10 degrees or more from the t/stat.
Turned my Mokita into a Steaming Demon mate and never looked back.... 8-)
MLG have the same Watlow 935 used for $199. +$25 for the shot timer.
THE ORIGINAL
Single line display, 1/32 DIN size (45 mm x 22 mm) Temperatures displayed to nearest whole degree. Optional shot timer add-on kit now available for $25.
Thats pretty expensive considering its used and you can buy a Watlow SD3C for only $81US more.
As far as my understanding goes with the PID the steam function will keep your steam at a steam temperature. At the moment its just like the brew thermostat where there is a big temperature difference between the element being on and off. The PID just controls this tighter.
My PID does not have steam control so I have no experience of this function but the way I look at it is once I start steaming the element cant maintain the temperature therefore it wont switch off on me. I tend the boiler by bleeding water off to create some headspace, let the temp rise and bleed off steam till it stops spluttering. The PID gives me the temperature readout so I bleed some water off at 100 degrees and then bleed steam off a couple of times before commencing steaming at 140 degrees the thermostat will want to cut off at I think 145 degrees but the boiler wont get that high, the element cant keep up once steaming starts. If I need to leave it I just turn the steam off, turn it back on when I return.
I like the shot timer, it allows me to monitor the shot duration, I have it set for 30 seconds and aim stop the shot at 25 seconds. I find it helps me keep the grinder adjusted.
I dont have a PID yet. I cant justify the cost of a PIDKit at the moment because Im just about to embark on roasting, but I was going to go the DIY route of making my own too but didnt get too far.
As far as my understanding goes with the PID the steam function will keep your steam at a steam temperature. At the moment its just like the brew thermostat where there is a big temperature difference between the element being on and off. The PID just controls this tighter.
PM me your email address tashie I might have some info of use to you in your quest.
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