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en:netzer:servo [2014/01/04 18:30] svesch |
en:netzer:servo [2014/10/03 17:11] svesch |
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| + | ====== Connection of a scale model servo ====== | ||
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| + | <note important>For this functionality the **[[io_project|IO project]]** (base or pro) must be [[fwupdates|uploaded]] to Netzer.</note> | ||
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| + | {{ :servo.png?nolink& |Servo at Netzer playground}} | ||
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| + | The pulse outputs IO3 and SPI_INT can be directly connected to conventional [[wp>Servo_%28radio_control%29|scale model servos]]. | ||
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| + | The pulse input of the servos is directly connected to IO3 or SPI_INT. Of course, mass is connected to mass. The voltage supply should be about 5\ V. | ||
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| + | Such a servo motor requires a periodic signal at the pulse input with the periodic time 20\ ms. At the beginning of a period the servo awaits a positive pulse. The pulse length defines the position of the servo arm. For the three positions **left**, **center** and **right**, the values 1\ ms, 1,5\ ms and 2\ ms have proved of value, some models may deviate. | ||
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| + | At the Netzer, the settings should be carried out as shown in the figure (IO configuration page). | ||
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| + | {{ servoconfig.gif?nolink& |Servo configuration}} | ||
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| + | The periodic time results from the internal 16-bit counter for continuous pulse signals: 65536\ *\ 400\ ns\ =\ 26,21\ ms. | ||
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| + | Some servos can definitely cope with 13.1\ ms (unit\ =\ 200\ ns), you should just try it. The advantage of using the smaller unit is that the servo may be addressed in smaller steps. | ||
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| + | In the following please find a table with some example values. Due to the deviations in the periodic times, the values probably require slight adjustments. | ||
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| + | ^ Unit^ Leftmost = 1\ ms ^ Central position = 1,5\ ms ^ Rightmost = 2,0\ ms ^ | ||
| + | | 400 ns | 2375 (0x947) | 3750 (0xea6) | 5125 (0x1405) | | ||
| + | | 200 ns | 4750 (0x128e) | 7500 (0x1d4c) | 10250 (0x280a) | | ||
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