Wiki source code of Tutorial 1 - als
Last modified by ssm on 2025/01/30 12:05
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| author | version | line-number | content |
|---|---|---|---|
| 1 | === T1A1: Important Thoughts === | ||
| 2 | |||
| 3 | ===== a) a real-time system ===== | ||
| 4 | |||
| 5 | The railway is a real-time system because it is a reactive system were the environment causes and dictates the interaction. | ||
| 6 | |||
| 7 | Furthermore there are real time constrains for reaction time of the system because a delayed reaction may cause an accident. | ||
| 8 | |||
| 9 | ===== b) an embedded system ===== | ||
| 10 | |||
| 11 | The railway controller needs special hardware, protocols and embedded processors to interact with components. | ||
| 12 | |||
| 13 | It does not need any keyboard or display to run and function correctly. | ||
| 14 | |||
| 15 | So it is not a standalone system for a desktop PC but a an embedded system integrated into to the railway. | ||
| 16 | |||
| 17 | ===== c) a safety-critical system ===== | ||
| 18 | |||
| 19 | It is a safety-critical system because most failures will directly endanger environment and hence people in and around the train. | ||
| 20 | |||
| 21 | So if the system crashes or hangs up the environment will not stop as well, so each error has safety-critical aspects. | ||
| 22 | |||
| 23 | === T1A2: C Interface === | ||
| 24 | |||
| 25 | ===== Plan ===== | ||
| 26 | |||
| 27 | (% style="margin-left: 30.0px;" %) | ||
| 28 | ~1. Leave KH_ST_1 | ||
| 29 | |||
| 30 | * Set point 8 straight and 9 to branch | ||
| 31 | * Power KH_ST_1 and KH_ST_6 forward with 60 | ||
| 32 | |||
| 33 | (% style="margin-left: 30.0px;" %) | ||
| 34 | 2. Pass KIO_LN_1 | ||
| 35 | |||
| 36 | * | ||
| 37 | ** Power KIO_LN_1 foward with 60 | ||
| 38 | |||
| 39 | (% style="margin-left: 30.0px;" %) | ||
| 40 | 3. Goto inner circle and enter IC_ST_1 | ||
| 41 | |||
| 42 | * | ||
| 43 | ** Set point 27 & 28 straight | ||
| 44 | ** Set point 29 to branch | ||
| 45 | ** Set point 24 straight | ||
| 46 | ** Power OC_ST_0 foward with 60 | ||
| 47 | ** Power IC_ST_4 reverse with 60 | ||
| 48 | ** Power IC_ST_1 reverse with 60 | ||
| 49 | |||
| 50 | (% style="margin-left: 30.0px;" %) | ||
| 51 | 4. Slow down | ||
| 52 | |||
| 53 | * | ||
| 54 | ** Wait for contact 1 of IC_ST_1 triggered | ||
| 55 | ** Power IC_ST_1 reverse with 20 | ||
| 56 | |||
| 57 | (% style="margin-left: 30.0px;" %) | ||
| 58 | 5. Stop and wait | ||
| 59 | |||
| 60 | * | ||
| 61 | ** Wait for contact 0 of IC_ST_1 triggered | ||
| 62 | ** Brake on IC_ST_1 | ||
| 63 | ** Wait 5 sec | ||
| 64 | |||
| 65 | (% style="margin-left: 30.0px;" %) | ||
| 66 | 6. Leaving IC_ST_1 to outer circle | ||
| 67 | |||
| 68 | * | ||
| 69 | ** Set point 20 straight | ||
| 70 | ** Set point 16, 17, 18 to branch | ||
| 71 | ** Power IC_ST_1 reverse with 60 | ||
| 72 | ** Power IC_ST_0 reverse with 60 | ||
| 73 | ** Power OC_ST_4 foward with 60 | ||
| 74 | |||
| 75 | (% style="margin-left: 30.0px;" %) | ||
| 76 | 7. Pass KIO_LN_1 | ||
| 77 | |||
| 78 | * | ||
| 79 | ** Power KIO_LN_0 foward with 60 | ||
| 80 | |||
| 81 | (% style="margin-left: 30.0px;" %) | ||
| 82 | 8. Enter KH_ST_1 | ||
| 83 | |||
| 84 | * | ||
| 85 | ** Set point 0 and 1 to branch | ||
| 86 | ** Set point 2, 3, 4 straight | ||
| 87 | ** Power KH_ST_0 foward with 60 | ||
| 88 | ** Power KH_ST_1 foward with 60 | ||
| 89 | |||
| 90 | (% style="margin-left: 30.0px;" %) | ||
| 91 | 9. Slow down | ||
| 92 | |||
| 93 | * | ||
| 94 | ** Wait for contact 0 of KH_ST_1 triggered | ||
| 95 | ** Power KH_ST_1 forward with 20 | ||
| 96 | |||
| 97 | (% style="margin-left: 30.0px;" %) | ||
| 98 | 10. Stop and wait | ||
| 99 | |||
| 100 | * | ||
| 101 | ** Wait for contact 1 of KH_ST_1 triggered | ||
| 102 | ** Brake on KH_ST_1 | ||
| 103 | ** Wait 5 sec | ||
| 104 | |||
| 105 | (% style="margin-left: 30.0px;" %) | ||
| 106 | ~11. Continue at 1. | ||
| 107 | |||
| 108 | ===== Code ===== | ||
| 109 | |||
| 110 | [[attach:T1A2_Controller.c]] | ||
| 111 | |||
| 112 | === T1A3: Reality vs. Simulation === | ||
| 113 | |||
| 114 | ===== 1. Differing Expectations ===== | ||
| 115 | |||
| 116 | There were no real initial expectations (preventing disappointments). | ||
| 117 | |||
| 118 | But I expected modelGUI and controller-simulation to be a bit more stable in cases of restarts after recompiling. | ||
| 119 | |||
| 120 | ===== 2. Expected differences between the simulation and the real model railway ===== | ||
| 121 | |||
| 122 | * Reactions to e.g. speed changes will not be immediate in the real model railway as they are in the simulation due to physical processes. | ||
| 123 | * No all trains will have the same behaviors in cases of speed, acceleration and breaking. Each real engine will behave a bit different. | ||
| 124 | * Unreliable triggering contacts causing inaccuracies in calculation of speed or direction of triggering train. | ||
| 125 | * Simulation can proceed with errors. On the real model railway an illegal configuration of tracks will cause a short shot or derail. In the simulation such errors are indicated as e.g. E_MOTORMODE_MISMATCH or E_SPEED_MISMATCH but may have no effect on the simulation. | ||
| 126 | * It is possible to have high acceleration in simulation even if real trains may fall apart. | ||
| 127 | |||
| 128 |