"AND" Logic Exit Condition

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oakbarn
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"AND" Logic Exit Condition

Post by oakbarn »

It would be very nice to have some "AND" logic with Exit Conditions rather than just an "OR". I have two vessels heating water then holding, it would be nice if I could have

Exit Condition 1 Vessel A Temp => 170

AND

Exit Condition 2 Vessel B Temp => 157.

Then Exit

Right now, Either Vessel A or Vessel B reaching Temp causes a State Change.

I know that I could do this with separate states but they heat concurrently in the same state.
el_hombre
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Re: "AND" Logic Exit Condition

Post by el_hombre »

+1 for this.

Since 4.0 has gotten rid of WIN inputs, how would one go about handling a state transition that requires user involvement?

For example, say I have a process for mashing. The first step is heat up the mash tun water. Once that is done, (in the 3.x version) I would set a user input to transition to the mashing state once I have dumped the grain into the tun. I the past you would dump in the grain, press the web input button, and the BCS moves to the state of holding temp and recirculating starts.

I would assume we could use a DIN to signal to the BCS to transition to the next state. But there isn't a way to tell the 4.x to say "once temp probe x equals y, fire an alarm and wait for DIN a to be b before transitioning to the next state" (since state transitions use OR logic instead of AND).

This is an overly simplistic example I admit, but IMO states with multiple exit conditions should be AND's anyways, not OR's (or OR's should be the option).
JonW
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Re: "AND" Logic Exit Condition

Post by JonW »

el_hombre wrote:Since 4.0 has gotten rid of WIN inputs, how would one go about handling a state transition that requires user involvement?
State transitions are accomplished by simply pushing the state name button (clicking on it). That was the whole reason WIN's went away because their only use was to perform a state jump and all states are already showing on the screen for an immediate jump.

el_hombre wrote:But there isn't a way to tell the 4.x to say "once temp probe x equals y, fire an alarm and wait for DIN a to be b before transitioning to the next state" (since state transitions use OR logic instead of AND).
I don't quite understand what you mean by "wait for DIN a to be b", but there is now an exit condition called "Wait for Input", which can be triggered when your target temp is hit, then you can advance state if that is what you are talking about.

But yes, an AND condition could be beneficial.
brahn
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Re: "AND" Logic Exit Condition

Post by brahn »

I agree that an AND condition could be useful, and this is something we'll look at post-4.0.

Like Jon, I don't really see how not having Web Inputs has anything to do with using AND in exit conditions. The reason Web Inputs were removed is because there's essentially already a Web Input for every possible state transition whenever a process is running, so Web Inputs would be redundant. If you want an indicator that you need to push something to trigger a state transition, that's what the Wait for Input status in the Exit Conditions area does.
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