QB Robotics qbmove Advanced Kit User Manual page 82

Mixed configurations can be also achieved through a proper setup. In such a case we can think
of synchronous sub-systems which execute asynchronously w.r.t. each other.
Note that in a single-device system the synchronous mode is a nonsense.
In both cases there is always one central Node which manages the shared resources for the serial
communication (e.g. one or many USB ports) and which provides several ROS services to whom
wants to interact with the connected devices. This Node is called Communication Handler and it
is usually started in a separate terminal.
To properly set qbmove IDs for the Delta Kit, see the section User guide in:
https://qbrobotics.com/products/qbmove-advanced-kit-delta/
6.5.2.1 Details
To understand what is hiding under the hood, have a look at the C++ classes overview which
sums up all the main concepts of our ROS packages:
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Figure 6-11: Synchronous vs asynchronous control mode.
Please remember that in a multi-device configuration (e.g. for the Delta Kit
see 4.5 ID configuration), each qbrobotics device connected to your system
must have a unique ID.
Indeed, if any device shares the same ID with another one on the same
chain (all the qbmove devices have ID equals 1 when they are shipped from
qbrobotics) communication issues will lead to unpredictable behaviours,
i.e. no data sent or received can be trusted.