Establish Read Channel (2003) - GE RX3i User Manual

Chapter 7. Programming SRTP Channel Commands

Establish Read Channel (2003)

The Establish Read Channel command requests that a channel be associated with a remote PLC and that data
from the remote PLC be transferred (periodically) to the local PLC. The Command Block specifies the period, the
number of reads from the server (remote PLC) to perform, and the timeout allowed in waiting for each transfer
to complete. The first read is performed immediately, regardless of the period specified.
Example Command Block
Establish a channel (Channel 5) to a remote PLC at IP address 10.0.0.1. Return the COMMREQ Status word to
%R10. Read remote PLC registers %R50–%R57 to local PLC registers %R100–%R107. Repeat the read ten
times, once every 7 seconds, with a timeout of 500ms for each read.
Word 1
Word 2
Word 3
Word 4
Word 5
Word 6
Word 7
Word 8
Word 9
The term local PLC
Word 10
is used here to
Word 11
identify the client
Word 12
PLC—the PLC that
Word 13
initiates the
communications
Word 14
request.
Word 15
Word 16
The term remote
PLC is used here to
Word 17
identify the server
Word 18
PLC—the PLC that
Word 19
responds to the
Word 20
communications
Word 21
request.
Word 22
Word 23
Word 24–
27
Word 28–
31
(Word 7) Channel Command Number: Word 7 requests that a read channel be set up. If the command is
processed successfully, it will result in attempting the specified number of transfers from the server to the
client.
(Word 8) Channel Number: Word 8 specifies the channel to be used for the read. This value must be in the
range of 1–32. If the channel number is out of range, a command error indication will be placed in the
COMMREQ Status word. If the channel number is the same as a channel already in use, the channel will be re-
tasked to perform this new command.
116 PACSystems* RX7i & RX3i TCP/IP Ethernet Communications User Manual
Dec (Hex)
00017 (0011) Length of Channel command Data Block (17–25 words)
00000 (0000) Always 0 (no-wait mode request)
00008 (0008) Memory type of COMMREQ status word (%R)
00009 (0009) COMMREQ status word address minus 1 (%R10)
13
00000 (0000) Reserved
00000 (0000) Reserved
02003 (07D3) Establish Read Channel command number
00005 (0005) Channel number (5)
00010 (000A) Number of read repetitions (read 10 times)
00003 (0003) Time unit for read period (3=seconds)
00007 (0007) Number of time units for read period (every 7 seconds)
00050 (0032) Timeout for each read (500ms)
00008 (0008) Local PLC - Memory type at which to store data (%R)
Local PLC - Starting address at which to store data
00100 (0064)
(%R100)
Remote PLC - Memory type from which to read data
00008 (0008)
(%R)
Remote PLC - Starting address from which to read data
00050 (0032)
(%R50)
00008 (0008) Remote PLC - Number of memory units (8 registers)
00001 (0001) Remote PLC - Network Address type (IP Address)
00004 (0004) Remote PLC - Network Address length in words (4)
00010 (000A) Remote PLC - Register 1 of IP address (10)
00000 (0000) Remote PLC - Register 2 of IP address (0)
00000 (0000) Remote PLC - Register 3 of IP address (0)
00001 (0001) Remote PLC - Register 4 of IP address (1)
Remote PLC - Program Name (needed for access to
remote %P or %L) (zero-terminated and padded)
Remote PLC - Program Block (needed for access to
remote %L) (zero-terminated and padded)
GFK-2224Q