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