9. Maestro Settings Limitations

Mini Maestro serial baud rate limitations

On the Mini Maestro 12, 18, and 24, the following baud rates should not be exceeded, or the processor may become overloaded, causing degraded performance.

10–100 Hz 111–250 Hz 333 Hz
Serial mode: UART/USB chained* 200 kbps 115.2 kbps 115.2 kbps
Serial mode: Dual-port 115.2 kbps 57.6 kbps 57.6 kbps

* Assuming bytes are not sent and received simultaneously, as required for the Pololu protocol.

Micro Maestro pulse length limitations (high pulse rates only).

Most servos are designed for 50 Hz operation. Unless you know that you need high pulse rates, you can safely ignore this section.

The Micro Maestro has a restricted maximum pulse length for pulse rates of 67 Hz and higher. The restriction depends on the Servos available setting and is enforced automatically by the Maestro Control Center.

The maximum pulse lengths in microseconds are given below:

6 servos 5 servos 4 servos 1–3 servos
67 Hz 2448 2944 3000+ 3000+
71 Hz 2272 2736 3000+ 3000+
77 Hz 2112 2544 3000+ 3000+
83 Hz 1936 2336 2944 3000+
91 Hz 1776 2144 2688 3000+
100 Hz 1616 1936 2448 3000+

Mini Maestro servo pulse length limitations (high pulse rates only)

Most servos are designed for 50 Hz operation. Unless you know that you need high pulse rates, you can safely ignore this section.

On the Mini Maestro 12, 18, and 24, pulse rates of 200–333 Hz put restrictions on the servo pulse lengths. These restrictions apply to all servo channels, even if some are set to a lower pulse rate using the Period multiplier feature.

The following tables show allowed minimum and maximum pulse lengths, in microseconds, for a variety of combinations of pulse rates and servo numbers. All enabled servos must always satisfy the restrictions on some table row, so the easiest way to follow the restrictions is to pick a row, then configure minimums and maximums for specific channels according to the restrictions given in that row. However, you do not need to specify the ranges of your servos in advance: you can switch some channels off or adjust their positions to access a wider range on other channels. If your settings happen to violate these restrictions, the servo period might increase and the units of speed and acceleration limits will change accordingly, but the operation of the Maestro will not be affected in any other way.

For example, with a Mini Maestro 24 running at 250 Hz (a 4 ms period), you may use 12 servos with a range of 576–2880 μs and 6 servos with a range of 64–2880 μs. The remaining 6 channels must each be off or have their mode set to Input or Output (not Servo).

Allowed pulse ranges at 333 Hz:
Servos Min Max
6 64 2328
6 192 2648
12 64 1752
12 384 2456
6/6 384/64 2072
18 64 1176
18 576 2264
24 768 2072
Allowed pulse ranges at 250 Hz:
Servos Min Max
6 64 3000+
12 64 2752
12 384 3000+
6/6 384/64 3000+
18 64 2176
18 576 3000+
12/6 576/64 2880
24 64 1600
24 768 3000+
18/6 768/64 2688
Allowed pulse ranges at 200 Hz:
Servos Min Max
6 64 3000+
12 64 3000+
6/6 384/64 3000+
18 64 3000+
12/6 576/64 3000+
24 64 2600
24 768 3000+
18/6 768/64 3000+