GE 90-30 PLC Switch User Manual


 
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TCP/IP Ethernet Communications User’s Manual - August 1997 GFK-1084B
(Word 17) Remote PLC - Number of Memory Units: Word 17 specifies the number of
bits, bytes or words to be read, determined by the remote PLC memory type specified.
For example, if the memory type is %I in bit mode this is the number of bits. If the
memory type is %R, this is the number of words. A maximum of 16384 bits/2048
bytes/1024 words of data may be specified.
(Word 18) Remote PLC - Network Address Type: Word 18 specifies the format of the
remote PLC address. In this release, Word 18 must contain the value 1 or 3. A value of 1
indicates a dotted-decimal IP address expressed using a separate register for each
decimal digit. A value of 3 indicates a Network Address name. See Example 2 for
information on using address type 3.
(Word 19) Remote PLC - Network Address Length: Word 19 specifies the length in words
of the remote PLC IP address. When an address type of 1 is specified Word 19 must
contain 4.
(Words 20 - 23) Remote PLC - IP Address: Words 20-23 specify the four integers, one
integer per word, of the dotted-decimal IP address of the remote PLC to be accessed.
(Words 24 - 27) Remote PLC - Program Name: Word 24 - 27 specify the case-sensitive,
zero-terminated and padded program name (also called task name, which can be found
through the PROG Station Manager command on the server Ethernet Interface) to be
used with access to remote %P or%L memory. These words are required only for access
to such memory and will be ignored if the Memory Type field is not %P or %L. See Note
below.
(Word 28 - 31) Remote PLC - Program Block Name: Words 28 - 31 specify the case-
sensitive, zero-terminated and padded program block name (which can be found in the
program block declaration in the server ladder program) to be used with access to remote
%L memory. These words are required only for access to such memory and will be
ignored if the Memory Type field is not %P or %L.
Note
The Program Name (words 24 - 27) and Program Block Name (words
28 - 31) must have each pair of ASCII characters reversed within the PLC
memory. For example, the name “MARY” (“M” = 4DH, “A” = 41H,
“R” = 52H, “Y” = 59H) would have 414D in the first word and 5952 in
the second word.