start_point_queue_mode fails if the robot has moved since being powered off

[ted-miller]

This is basically the same problem as #37.

It can also happen if restoring an old CMOS backup.

When you attempt to start_point_queue_mode, the pendant raises alarm OUT OF RANGE (DROP-VALUE). But the service call just returns The controller has an active Error: Can't turn on servo because: 'Servo power cannot be turned on' (0x3450). So, the message isn't necessarily wrong, it's just not helpful.

In my case, I was able to just reset the alarm and try again. But usually, this alarm requires you to verify the home-position before you can proceed.

I'm not yet sure how to detect this scenario so that we can provide a better error code.

[gavanderhoorn]

#182? Does robot_status::error_codes not list all active errors?

[ted-miller]

#182? Does robot_status::error_codes not list all active errors?

This particular problem is not that 'type' of error.

A traditional pendant error is caused by incorrect user behavior on the pendant. (Like hitting PLAY when servos are off.) This particular problem is more from the robot being in a bad programmatic state.