Protocol Connections
Two independent KAREL programs run on the controller:
| Program | tag | port | constant |
|---|---|---|---|
MAPPDK_SERVER |
S8 | 18735 | protocol.DEFAULT_PORT |
MAPPDK_LOGGER |
S7 | 18736 | protocol.LOGGER_PORT |
Comparing the two source files side by side, the main loop is
identical, both call the same HANDLE_CMD, and both support the
upstream commands and
extended commands in the tables above. Only
three things differ:
- tag and port
- the logger doesn't run
TP_CLS - the logger doesn't set
UFRAME[8]/UTOOL[8]; the server does that, and both setting it would conflict
So "logger" is a bit of a misleading name; it doesn't write logs. Its
purpose is to be a second connection: the main connection (S8) blocks
after sending movej until the move finishes, and that's when
position can be queried from the logger (S7) instead; that's exactly
how trajectory recording (MotionTracer) works. If you only ever use
a single connection, S7 doesn't need to be set up, see
controller setup.
Last updated: 2026-08-31