check for doubled PDO mappings

[mathias-luedtke]

As pointed out in #183 PDOs cannot be mapped twice. This patch checks for this case and stops further processing.

@JuliusGel: Can you test this fix, please.
I don't have access to a CANopen set-up right now, and it is triggered only in 301 init.

[JuliusGel]

We have tested this PR. This correctly prevents one object mapping in multiple PDO.

[JuliusGel]

There is an issue with this fix. If you call /driver/init then call /driver/shutdown and call /driver/init again there will be an exception thrown about PDO mapped twice.

[mathias-luedtke]

mapping needs to be reset in
https://github.com/ros-industrial/ros_canopen/blob/indigo-devel/canopen_master/src/pdo.cpp#L173
and
https://github.com/ros-industrial/ros_canopen/blob/indigo-devel/canopen_master/src/pdo.cpp#L186

[mathias-luedtke]

There is an issue with this fix.

Should be rescolved by auto-unmap.

[mathias-luedtke]

@JuliusGel: does the new version work for you?

[JuliusGel]

@ipa-mdl : Hi, unfortunately we had made a decision not use ros_canopen due to hardware issues. I therefore am not able to test this anymore. I could only provide a dcf that was failing if that is of any interest.

[mathias-luedtke]

I could only provide a dcf that was failing if that is of any interest.

This would be great :)

[JuliusGel]

I am attaching the eds file that had this problem.
We were using it with Trinamic motor PD-1160. Hope this is useful.
TMCM-1160_V318.zip

[jacknlliu]

@ipa-mdl What's the status of this PR? We have the same issue, is there a solution for this issue? Can ros_canopen support multiple-pdos mapping now?

[mathias-luedtke]

@jacknlliu: It must be rebased and tested.

[jacknlliu]

@ipa-mdl actually this PR only check the mapping and don't make ros_canopen work with this situation. If you have solutions to make doubled PDOs work with ros_canopen, we can test it.

[mathias-luedtke]

The current design does not allow ambiguous PDO mappings.
This PR will just make it report the problem.