User Tools

Site Tools


Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
mission:resources:picoreflow [2016/10/19 21:31]
chrono [WiFi/Raspberry Pi pottery kiln controller]
mission:resources:picoreflow [2021/08/30 22:25] (current)
chrono [Simulation]
Line 99: Line 99:
 | {{:mission:resources:picoreflow-ssr-signal-pulldown-connection.png?320|}} | {{:mission:resources:picoreflow-ssr-signal-pullup-connection.png?320|}} | | {{:mission:resources:picoreflow-ssr-signal-pulldown-connection.png?320|}} | {{:mission:resources:picoreflow-ssr-signal-pullup-connection.png?320|}} |
  
-The default configuration has historically been to use the PullDown config, i.e. when you pull GPIO23 low the heater is on and when you pull GPIO23 high the heater is off. Please keep in mind that you'll have to have some script/code in your setup that makes sure that GPIO23 is pulled high as soon as the system has booted (to be sure the heater is off) or change your setup to PullUp connection instead if you don't want to worry/bother.+ 
 +The default configuration has historically been to use the PullDown config, which results in an inverted control logic: When you pull GPIO23 lowthe heater is switched on and when you pull GPIO23 highthe heater is switched off.  
 + 
 +<WRAP round important> 
 +**Please keep in mind that you'll have to have some script/code in your setup that makes sure that GPIO23 is pulled high as soon as the system has booted** (to be sure the heater is off) or change your setup to PullUp configuration insteadif you don't want to worry/bother. 
 +</WRAP>
 ==== Cooling ==== ==== Cooling ====
  
Line 211: Line 216:
  
 === Calculation === === Calculation ===
-Every <x 14>\Delta t</x> the following calculations are performed:+Every $\Delta tthe following calculations are performed:
  
  
 Thermal energy flowing into the heating element: Thermal energy flowing into the heating element:
  
-<x 14> +Q_h = P_heat * \Delta t $
-Q_h = P_heat * \Delta t +
-</x>+
  
 Temperature change of heating element by heating: Temperature change of heating element by heating:
  
-<x 14> +\Delta T_h1 = Q_h / C_heat $
-\Delta T_h1 = Q_h / C_heat +
-</x> +
  
 Temperature change between heating element and oven: Temperature change between heating element and oven:
  
-<x 14> +P_ho = (T_h - T) / R_ho $
-P_ho = (T_h - T) / R_ho +
-</x>+
  
-<x 14> +\Delta T_1 = (P_ho / C_oven) * \Delta t $
-\Delta T_1 = (P_ho / C_oven) * \Delta t +
-</x>+
  
-<x 14> +\Delta T_h2 = - (P_ho / C_oven) * \Delta t $
-\Delta T_h2 = - (P_ho / C_oven) * \Delta t +
-</x>+
  
 Temperature change between oven and environment Temperature change between oven and environment
  
-<x 14> +P_oe = (T - T_env) / R_oe $
-P_oe = (T - T_env) / R_oe +
-</x>+
  
-<x 14> +\Delta T_2 = - (P_oe / C_oven) * \Delta t $
-\Delta T_2 = - (P_oe / C_oven) * \Delta t +
-</x>+
  
-Temperature of oven and heating element at this timestep:+Temperature of oven and heating element at this time-step:
  
-<x 14> +T = T_old + \Delta T_1 + \Delta T_2 $
-T = T_old + \Delta T_1 + \Delta T_2 +
-</x>+
  
-<x 14> +T_h = T_h_old + \Delta T_h1 + \Delta T_h2 $
-T_h = T_h_old + \Delta T_h1 + \Delta T_h2 +
-</x>+