GE PACSystems RX7i Reference Manual

Chapter 6. Serial I/O, SNP & RTU Protocols
GFK-2222AD April 2018 205
6.1.6 Example COMMREQ Command Blocks for Serial Port Setup function
The following COMMREQ command blocks provide examples for configuring the various protocols. All
values are in decimal unless followed by an H indicating hexadecimal.
Note that an example is not provided for Message Mode, but it can be setup with a command block
similar to the one for Serial I/O, with a value of 7 for the protocol selector.
Example COMMREQ Command Block for Configuring SNP Protocol
Values
Meaning
Address
16
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
1 = SNP
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
not used (SNP always chooses NONE by default)
Flow Control
Address + 12
0 = None, 1 = 10ms, 2 = 100ms, 3 = 500ms
Turnaround Delay
Address + 13
0 = Long, 1 = Medium, 2 = Short, 3 = None
Timeout
Address + 14
not used (SNP always chooses 8 bits by default)
Bits Per Character
Address + 15
0 = 1 Stop Bit, 1 = 2 Stop bits
Stop Bits
Address + 16
not used
Interface
Address + 17
not used (SNP always chooses 4-wire mode by default)
Duplex Mode
Address + 18
user-provided
82
Device identifier bytes 1 and 2
Address + 19
user-provided
82
Device identifier bytes 3 and 4
Address + 20
user-provided
82
Device identifier bytes 5 and 6
Address + 21
user-provided
82
Device identifier bytes 7 and 8
82
The device identifier for SNP Slave ports is packed into words with the least significant character in the least significant byte
of the word. For example, if the first two characters are “A” and “B,” the Address + 18 will contain the hex value 4241.

GE PACSystems RX7i Specifications

General

Brand	GE
Model	PACSystems RX7i
Category	Controller
Language	English