Alcorn Mcbride 1746-SMPTE, Руководство пользователя

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Using the Module as a SMPTE Generator 11
SMPTE
Generator
Monitoring the Status of the Generator
The 1746-SMPTE generator communicates its status to the PLC through the
Input File. See the Module I/O Space chapter for a diagram of the Input File.
Current Time
The current output SMPTE time code is always available through four words in
the PLC Input File.
Word 0, hours, will always be between 0 and 23, inclusive.
Word 1, minutes, will always be between 0 and 59, inclusive.
Word 2, seconds, will always be between 0 and 59, inclusive.
Word 3, frames, will always be between 0 and 29, inclusive.
Note: Word 3, frames, can change 30 times per second. This could impact your
programming technique if your program’s scan time exceeds 33 milliseconds.
Current Frame Rate
The low byte of word 1 in the Input File always contains the number 24, 25, or
30 to indicate the frame sequence of the output time code. For example, 24
frame time code always rolls over from frame number 23 to frame number 0.
No distinction is made between 23.976 and 24 frame rates, or between 29.97 and
30 frame rates.
Locked
This bit will always be clear (zero) when generating time code. It is used only
by the SMPTE reader to indicate incoming time code lock.
Self-Generating
Whenever the internal SMPTE generator is running, this bit in the Input File is
set (one). If the internal generator switches into idle mode, this bit will be
cleared.
Drop Frame
If the output time code has its drop frame flag set, then this bit will be set. If the
output code is not a drop frame code, then this bit will be clear.