TMC 188/40 Motion Control Module
V Memory
Delta Computer Systems, Inc. 360/254-8688
17
VINIT
points to the location containing the axis initialization parameters.
VREAD
points to the location the P/C monitors for position and status information.
VWRITE
points to the location where the P/C writes the dynamic control parameters.
CHECKSUM
is the sum of all the values in the first seven WY registers. It is used to verify the
validity of the WY registers. If this value is incorrect, the TMC 188/40 will not operate and the P/C
LED on the front panel will flash red and green at a constant rate.
Axis Initialization Process
VINIT values are moved to the TMC 188/40 only when the 'P' command is issued by the P/C to the
VWRITE location (see COMMAND parameters on pages 38 - 42). Once issued, it takes two P/C
scan cycles to complete the TMC 188/40 axis initialization process. Do not issue a new command
until the 'P' (ASCII 80) has been cleared from the COMMAND location in V Memory by the TMC
188/40.
NOTE
: If a new command is issued during the initialization scans, it will cause the initialization process to
abort.
TMC 188/40TA modules with the pressure mode enabled have more VINIT locations (see Appendix
B for details).
TMC 188/40 initialization process:
P/C Scan n -
Change initialization parameter(s) in V Memory
Set the VWRITE V Memory command location to decimal 80 (P)
P/C Scan n+1 -
TMC 188/40 reads initialization parameters from V Memory
TMC 188/40 processes the initialization parameters
NOTE
: Once the TMC 188/40 is initialized, changes in the WY registers will not take effect until the power
is cycled or the module is reset.
