[Paparazzi-devel] Servo outputs are different from PPM input measurements

[C. Y. Chen]

hi,

im using Lisa/M 2.0, when i install Lisa/M to my aircraft, i found
that the travel of servos significantly smaller than that i just
directly connect servos to receiver.

from oscilloscope, the measurement of  signal directly from receiver
is 1966,1553,1141(max, neutral, min in microsecond,1th channel),
measurement form Lisa/M servo output pin is 1783, 1555, 1275(these
three  value are the same with GCS tools:message, ACTUATOR part).
Other channels are different in max, min value.too. The measurement of
PPM encoder output seems correct(from GCS tool : message, PPM part).
Below is my setting in airframe.xml  and radio.xml i've upload to
Lisa/M, i have no idea why servo signals Lisa/M outputs are different
from that PPM encoder outputs.Do i miss some configurations?

thanks,

Chen

<!-- commands section -->
  <servos>
    <servo name="AILERON"      no="0" min="1141" neutral="1553" max="1966"/>
    <servo name="THROTTLE"      no="2" min="1108" neutral="1108" max="1934"/>
    <servo name="ELEVATOR"      no="1" min="1821" neutral="1408" max="995"/>
    <servo name="RUDDER"        no="3" min="1768" neutral="1520" max="1272"/>
  </servos>

  <commands>
    <axis name="ROLL"     failsafe_value="0"/>
    <axis name="THROTTLE" failsafe_value="0"/>
    <axis name="PITCH"    failsafe_value="0"/>
    <axis name="YAW"      failsafe_value="0"/>
  </commands>

  <rc_commands>
    <set command="ROLL"      value="@ROLL"/>
    <set command="THROTTLE"  value="@THROTTLE"/>
    <set command="PITCH"     value="@PITCH"/>
    <set command="YAW"  value="@YAW"/>
  </rc_commands>

  <command_laws>
    <set servo="THROTTLE"    value="@THROTTLE"/>
    <set servo="RUDDER"      value="@YAW"/>
    <set servo="ELEVATOR"    value="@PITCH"/>
    <set servo="AILERON"        value="@ROLL"/>
  </command_laws>

  <auto_rc_commands>
  </auto_rc_commands>

  <section name="AUTO1" prefix="AUTO1_">
    <define name="MAX_ROLL" value="RadOfDeg(50)"/>
    <define name="MAX_PITCH" value="RadOfDeg(40)"/>
  </section>


and radio.xml:

<!DOCTYPE radio SYSTEM "radio.dtd">
<radio name="T10CHG_RMITEC" data_min="700" data_max="2100"
sync_min="5600" sync_max="20000" pulse_type="NEGATIVE">
  <channel ctl="A" function="ROLL" min="950" neutral="1553" max="2100"
average="0"/>
  <channel ctl="B" function="PITCH"      min="2100" neutral="1408"
max="950" average="0"/>
  <channel ctl="C" function="THROTTLE"    min="950" neutral="1108"
max="2100" average="0"/>
  <channel ctl="D" function="YAW"     min="2100" neutral="1520"
max="950" average="0"/>
  <channel ctl="E" function="MODE"  min="1140" neutral="1520"
max="1951" average="10"/>
  <channel ctl="F" function="NONEA"     min="966"  neutral="1500"
max="2025" average="0"/>
  <channel ctl="G" function="NONEB"     min="966"  neutral="1500"
max="2025" average="0"/>
</radio>