Hi, I've started a Python module to control heaters for extruders and build platforms. Right now, it does two things: 1) Bypasses the PID controller during the initial heating period. When the heater temperature is below the set temperature by some value (configurable), a constant value (configurable) will be sent to the PWM controller. When the heater temperature is within range, the PID controller will be enabled and its output is forwarded to the PWM. 2) Monitors the heater temperature, and when it is within a range (configurable) of the set temperature for a period of time (configurable), it will set a bit indicating that the heater is ready. This bit is used by the "set temp and wait" M codes.
What I want to do next is add some fault protection. Here are my ideas. Comments welcome. 1) When the machine power is off, set the PWM output to 0. The set temperature will probably remain set where it is. 2) The Marlin firmware has code to prevent cold extrusion. I am thinking about adding something similar with an extruder disable/enable pin. This pin would also be used to disable the extruder if a fault is detected. What happens if a motion command is sent to a motor that is disabled? 3) Temperature read fault detection. If there is a fault when reading the temperature, the pwm output will be set to 0, a fault pin will be set, and the extruder will be disabled. I don't think that this should stop the whole machine. The error state will stay set until the set temperature has been set to 0. The module that reads the temperature will have a fault output pin and will be responsible for indicating a fault. For the existing ReadTemp, I would think a reading <0 and >325 would be an error. I'll be starting on a thermocouple based input, which indicates faults independently of the temperature reading. Troy ------------------------------------------------------------------------------ Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with <2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031&iu=/4140/ostg.clktrk _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
