Five Basic Questions

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oakbarn
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Five Basic Questions

Post by oakbarn »

Five Basic Questions that have come to mind:
Describing the BCS 462:
Along with the eight temperature sensor inputs, the BCS-462 provides eight 5V discrete inputs, and four web-based user inputs. All inputs can trigger controller responses. 18 low-current 5V discrete outputs are provided for relay control. Six of the outputs can be controlled by PWM, differentially by a temperature input, or under complete PID control. The remaining 12 outputs provide on/off control.

1. eight temperature sensor inputs : Sensor Inputs are fairly straight forward and explained in the Wiki and Discussion.
2. eight 5V discrete inputs. Does this mean ? You can have a signal that comes into the BCS to trigger a state. What are devices that can have an Input? Is there a “list” of devices and their uses? Is there a list of specific examples?
3. four web-based user inputs: Are these simply “Virtual Buttons” on the Web Based user interface (ie Main Control Panel of the BCS on your computer)? If this is correct then therefore only available when you are connected using the Web Based user interface (ie Main Control Panel of the BCS on your computer)?
4. 18 low-current 5V discrete outputs are provided for relay control. Six of the outputs can be controlled by PWM, differentially by a temperature input, or under complete PID control.: What is PWM? What does under complete PID control mean?
5. I also am not positive what the world “assert” means in the Wiki. I assume means that it is “active” or fires.


OK, a lot more than 5 questions, but trying to wrap my head around the concepts involved.
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Re: Five Basic Questions

Post by brahn »

oakbarn wrote: 2. eight 5V discrete inputs. Does this mean ? You can have a signal that comes into the BCS to trigger a state. What are devices that can have an Input? Is there a “list” of devices and their uses? Is there a list of specific examples?
Yes, as long as it's an on/off signal. An example might be a float switch. I don't know of a comprehensive list of devices, but if it can issue an on/off signal at 5V it should work.
oakbarn wrote: 3. four web-based user inputs: Are these simply “Virtual Buttons” on the Web Based user interface (ie Main Control Panel of the BCS on your computer)? If this is correct then therefore only available when you are connected using the Web Based user interface (ie Main Control Panel of the BCS on your computer)?
Yes, these are just buttons on the web interface.
oakbarn wrote: 4. 18 low-current 5V discrete outputs are provided for relay control. Six of the outputs can be controlled by PWM, differentially by a temperature input, or under complete PID control.: What is PWM? What does under complete PID control mean?
PWM is Pulse Width Modulation. It basically turns the output on and off really quickly so you can essentially run a device at a fractional power level. I believe it's mostly used with heating elements where you may not want it on full blast all the time.

PID control more or less uses PWM to maintain a set temperature. Unless you know what you're doing, you probably want to use Hysteresis/Differential temperature mode instead.
oakbarn wrote: 5. I also am not positive what the world “assert” means in the Wiki. I assume means that it is “active” or fires.
Correct. "active" or "turns on"
oakbarn wrote: OK, a lot more than 5 questions, but trying to wrap my head around the concepts involved.
Keep 'em coming!
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Re: Five Basic Questions

Post by oakbarn »

Thanks for the answers.

For example, I could have the flame detector switch
http://www.amazon.com/Intelligent-3-3-5 ... v+switches

on a DIN. When It "asserts", I could start a timer process for "Flame On" :!:
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Re: Five Basic Questions

Post by brahn »

Yes, in theory that would work. However, I know that Derrin from Brewer's Hardware was testing out something similar to that and wasn't able to get it working to a point where he was happy with it. It had too many issues with false positives and false negatives. It doesn't mean that it won't work, or that you shouldn't try it, but know that it may give you problems.

If you did get it working, I think it would be better to detect when the flame is out but the burner output is on. That way you could re-cycle the burner and get it ignited again instead of leaking gas everywhere. It's usually good enough to assume "Flame On" when the burner output is turned on.
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Re: Five Basic Questions

Post by oakbarn »

I was not thinking about gas. I wrote a little MS Access program and I have a Flame On Button so I know how long it takes to heat my strike water. Useful when planning. I started a thread on DINs under Senors et all hoping to get some insight from current users on their inputs.
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Re: Five Basic Questions

Post by oakbarn »

PWM Again: I have read the definition on the internet and understand the principle, but I am not sure how this would apply to an output. Since the BCS output is really a control signal unless you wanted to light an LED and have it pulse, I cannot see how PWM would be useful for an Output on the BCS. How would you use one of the PWM outputs in a brewery setup since you would normally be controlling an SSR with the output that would in turn power a device (such as a pump that would benefit from PWM.)
Do you need to use one of the available PWM outputs to control an SSR that has a motor as the device?
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Re: Five Basic Questions

Post by JonW »

PWM outputs are most useful for electric heating elements in the brew systems. The PID combined with the PWM can start to cut power to a heating element as it approaches the target setpoint to keep you from overshooting the temperature. Most pumps don't function well on PWM outputs as well as things like gas valves since the output can't be controlled with a rapid on/off.
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