Lost communication with I/O device

HainingLuo

Hi all, 

I have been working with a dual arm YuMi and recently an error 'Lost communication with I/O device' has been constantly raised from the flexpendent. The device that lost communication was either the left gripper or the right gripper. I have seen this error a few times before but recently it became much more often.

I originally assumed that it might be a hardware connection issue as suggested by the description, however, the connection was always re-established 5 seconds after the loss of communication. If the issue is indeed the connection, how come the communication was not lost permanently? Could it be caused by other reasons? I have external cameras mounted on the grippers, could they be the reason that connection was dropping constantly? If I do need to open YuMi up to check the connection, could anyone kindly pointing me out on where can I find definitions of the ports? (I have checked the manual and the product specification but so far no luck finding such information.) 

Here is the complete message:

Description

The previously working communication with I/O device Hand_L with address 192.168.125.40 on network EtherNetIP has been lost.

Consequences

It is not possible to access the I/O device itself or I/O signals on the I/O device since it is currently not communicating with the controller.

Causes

The I/O device may have been disconnected from the system.

Actions

1) Make sure that the network cable is connected to the controller.

2) Make sure the I/O device is correctly powered. 

3) Make sure the cabling to the I/O device is correctly connected.

Any suggestion is appreciated! Many thanks in advance.

graemepaulin

Is the LH arm moving when the communication is lost?
If it is it could be a cable break or a connector moving so it is making and breaking.

Does it loose communication with any other devices, like the right hand griper?

HainingLuo

graemepaulin said:

Is the LH arm moving when the communication is lost?
If it is it could be a cable break or a connector moving so it is making and breaking.

Does it loose communication with any other devices, like the right hand griper?

Thank you graeme! It happened both when the arm was moving and stationary. One thing I noticead was that the 6th joint slides a little bit (motors off) due to the weight from the extra camera, so maybe this little movement could also be the cause of the loss of connection? 

The right gripper has exactly the same problem which makes me questioning whether this is actually from the cable connection or it is the extra weight caused unexpected movement and the gripper automatically disconnected after this displacement became significant. Do you think the second assumption could be possible? Thanks!

graemepaulin

I think is has something to do with the electrical connection between the gripper and the arm.
The  standard YuMi gripper is not designed to have this extra weight on it so it could be distorting enough to loose connection.
Can you remove the camera and run the robot to see if the extra camera is causing the issue?

HainingLuo

graemepaulin said:

I think is has something to do with the electrical connection between the gripper and the arm.
The  standard YuMi gripper is not designed to have this extra weight on it so it could be distorting enough to loose connection.
Can you remove the camera and run the robot to see if the extra camera is causing the issue?

Sorry for the late update. I finally fixed the problem by upgrading the Robotware to 6.13 and the errors just disappeared. I am not sure this is the sole reason of the error though. I have also changed the network used to communicate with YuMi and some of my RAPID scripts. But if anyone sees this error in the future and you are using an old version (I was using 6.07), then upgrading Robotware would be my first advice.