LS Industrial Systems GIMAC-II, User Manual

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9.4.2 PRECISION SYNC
The Host system transmits START_PRECI_SYNC frame to GMPC. And The Host system
stores the time when the first frame and the first bit is started transmitting (A1) at this
point.
GMPC stores the point that the first frame and the first bit of START_PRECI_SYNC frame
is received (B1).
GMPC transmits REQUEST_ADJUST frame to the Host system. And GMPC stores the
time when the first frame and the first bit is started transmitting (B2) at this point.
The Host system stores the point that the first frame and the first bit of
REQUEST_ADJUST frame is received (A2)
The Host system transmits TIME_ADJUST frame to GMPC. And this frame includes the
starting point that TIME_ADJUST frame is transmitted and the time data (A1,A2) which
has already been stored.
RTC (Real Time Clock), inside of GMPC, is calibrated by using the time data A1,A2
which have been received and B1,B2 stored in GMPC.
ADJ = ((A2 – A1) – (B2 – B1)) / 2
T_NEW = T_OLD + ADJ
Host System GMPC-III
START_PRECI_SYNC
REQUEST_ADJUST
TIME_ADJUST
END_PRECI_SYNC
A1
A2
B1
B2