GE PACSystems RX7i Reference Manual page 217

Chapter 6. Serial I/O, SNP & RTU Protocols
Example COMMREQ Data Block for Configuring RTU Protocol
Values
Address 13, or 17
Address + 1 0 = No Wait (WAIT mode not supported)
Address + 2 0008 = %R, register memory
Zero-based number that gives the address of the
Address + 3 COMMREQ status word (for example, a value of 99 gives
an address of 100 for the status word)
Address + 4 not used
Address + 5 not used
Address + 6 FFF0H
Address + 7 3 = RTU
Address + 8 0 = Slave
Address + 9 See COMMREQ Command Block Parameter Values.
Address + 10 0 = None, 1 = Odd, 2 = Even
Address + 11 0 = Hardware, 1 = None
Address + 12 not used
Address + 13 not used
Address + 14 not used (RTU always chooses 8 bits by default)
Address + 15 not used (RTU always chooses 1 stop bit by default)
Address + 16 not used
Address + 17 0 = 2-wire, 1 = 4-wire, 2 = 4-wire transmitter always on
Address + 18 Station Address (1-247)
Address + 19 Count of 100 µs units (0 = 3.5 character times)
Address + 20 not used
Address + 21 not used
Address + 22 Count of 10 ms units (range 0-255)
83
The End-of-frame timeout and Receive-to-transmit delay values were added in Release 6.70 for the RX3i. They are discussed
in the RTU Slave Protocol section.
206 PACSystems* RX7i, RX3i and RSTi-EP CPU Reference Manual
Meaning
Data Block Length
WAIT/NOWAIT Flag
Status Word Pointer Memory Type
Status Word Pointer Offset
Idle Timeout Value
Maximum Communication Time
Command Word (serial port setup)
Protocol
Port Mode
Data Rate
Parity
Flow Control
Turnaround delay
Timeout
Bits per Character
Stop Bits
Interface
Duplex Mode
Device Identifier
83
End-of-frame timeout
Receive-to-transmit delay
83
GFK-2222AD