The serial data transmission unit 2, wherein said value read from the program by said CPU is determined considering a longest one of {HEAD ~ data holding intervals} of {TAIL ~ said plurality} of external slaves 
of
The serial data transmission unit 2 , wherein said value read from the program by said CPU is determined considering a longest one of { HEAD ~ data holding intervals } of { TAIL ~ said plurality } of external slaves
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH