SITL error "Unable to find parameter" - no longer possible to set params in SITL

I am trying to set params in a newly checked out SITL run but it is failing as follows:

$ python3 ~/ardupilot/Tools/autotest/sim_vehicle.py -v ArduCopter -f quad -L KSFO --console --map --udp
SIM_VEHICLE: Start
SIM_VEHICLE: Killing tasks
SIM_VEHICLE: Starting up at [37.619373, -122.376637, 5.3, 118.0] (KSFO)
SIM_VEHICLE: WAF build
SIM_VEHICLE: Configure waf
SIM_VEHICLE: "/home/user/ardupilot/modules/waf/waf-light" "configure" "--board" "sitl"
Setting top to                           : /home/user/ardupilot 
Setting out to                           : /home/user/ardupilot/build 
Autoconfiguration                        : enabled 
Setting board to                         : sitl 
Using toolchain                          : native 
Checking for 'g++' (C++ compiler)        : /usr/lib/ccache/g++ 
Checking for 'gcc' (C compiler)          : /usr/lib/ccache/gcc 
Checking for c flags '-MMD'              : yes 
Checking for cxx flags '-MMD'            : yes 
CXX Compiler                             : g++ 10.2.1 
Checking for need to link with librt     : not necessary 
Checking for feenableexcept              : yes 
Checking for HAVE_CMATH_ISFINITE         : yes 
Checking for HAVE_CMATH_ISINF            : yes 
Checking for HAVE_CMATH_ISNAN            : yes 
Checking for NEED_CMATH_ISFINITE_STD_NAMESPACE : yes 
Checking for NEED_CMATH_ISINF_STD_NAMESPACE    : yes 
Checking for NEED_CMATH_ISNAN_STD_NAMESPACE    : yes 
Checking for header endian.h                   : yes 
Checking for header byteswap.h                 : yes 
Checking for HAVE_MEMRCHR                      : yes 
Configured VSCode Intellisense:                : no 
Checking for program 'python'                  : /usr/bin/python 
Checking for python version >= 2.7.0           : 3.9.2 
Checking for program 'python'                  : /usr/bin/python 
Checking for python version >= 2.7.0           : 3.9.2 
Source is git repository                       : yes 
Update submodules                              : yes 
Checking for program 'git'                     : /usr/bin/git 
Checking for program 'size'                    : /usr/bin/size 
Benchmarks                                     : disabled 
Unit tests                                     : enabled 
Scripting                                      : enabled 
Scripting runtime checks                       : enabled 
Debug build                                    : disabled 
Coverage build                                 : disabled 
SITL 32-bit build                              : disabled 
Checking for program 'rsync'                   : /usr/bin/rsync 
'configure' finished successfully (0.747s)
SIM_VEHICLE: Building
SIM_VEHICLE: "/home/user/ardupilot/modules/waf/waf-light" "build" "--target" "bin/arducopter"
Waf: Entering directory `/home/user/ardupilot/build/sitl'
Embedding file locations.txt:Tools/autotest/locations.txt
Embedding file models/Callisto.json:Tools/autotest/models/Callisto.json
Waf: Leaving directory `/home/user/ardupilot/build/sitl'

BUILD SUMMARY
Build directory: /home/user/ardupilot/build/sitl
Target          Text (B)  Data (B)  BSS (B)  Total Flash Used (B)  Free Flash (B)
---------------------------------------------------------------------------------
bin/arducopter   3551596    170101   201320               3721697  Not Applicable

Build commands will be stored in build/sitl/compile_commands.json
'build' finished successfully (1.665s)
SIM_VEHICLE: Using defaults from (ardupilot/Tools/autotest/default_params/copter.parm)
SIM_VEHICLE: Run ArduCopter
SIM_VEHICLE: "/home/user/ardupilot/Tools/autotest/run_in_terminal_window.sh" "ArduCopter" "/home/user/ardupilot/build/sitl/bin/arducopter" "-S" "--model" "+" "--speedup" "1" "--slave" "0" "--defaults" "ardupilot/Tools/autotest/default_params/copter.parm" "-I0" "--home" "37.619373,-122.376637,5.3,118.0" "--uartA" "udpclient:127.0.0.1:5760"
SIM_VEHICLE: Run MavProxy
SIM_VEHICLE: "mavproxy.py" "--out" "127.0.0.1:14550" "--out" "127.0.0.1:14551" "--master" ":5760" "--sitl" "127.0.0.1:5501" "--map" "--console"
RiTW: Starting ArduCopter : /home/user/ardupilot/build/sitl/bin/arducopter -S --model + --speedup 1 --slave 0 --defaults ardupilot/Tools/autotest/default_params/copter.parm -I0 --home 37.619373,-122.376637,5.3,118.0 --uartA udpclient:127.0.0.1:5760
Connect :5760 source_system=255
Loaded module console
Loaded module map
Log Directory: 
Telemetry log: mav.tlog
Waiting for heartbeat from :5760
MAV> param set SIM_WIND_DIR 180
STABILIZE> Unable to find parameter 'SIM_WIND_DIR'
STABILIZE>

It used to work fine until this recent checkout of arducopter. I can see that the only param I can set is STAT_RUNTIME. Does anyone know what I have done wrong? Thanks.

Solved by deleting the ardupilot checkout that I had and doing a new git clone. params reappear. :slight_smile:

Okay, I spoke too soon. A new clone of ardupilot does indeed show all the params in SITL.

Buy when you run it the next time, all params disappear except STAT_RUNTIME. Really really weird. :-S