GE PACSystems RX7i Reference Manual

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

GE PACSystems RX7i Specifications

General

Brand	GE
Model	PACSystems RX7i
Category	Controller
Language	English