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