ProSoft Technology MVI71-GEC - Manual (Page 62)

Reference MVI71-GEC ♦ PLC 5 Platform
User Manual Generic ASCII Ethernet Communication Module
Page 62 of 86 ProSoft Technology, Inc.
May 11, 2011
These files have fixed formats that are discussed below. Data received by the
servers on the modules is passed to the read data file. The format of this file is
shown in the following table.
Word
Offset Description
0 Server Number for data received. If the word contains a value of -1, no
receive data is present. If the word contains a value from 0 to 4, the block
contains data from one of the servers in the module.
Received
Data
1 Number of characters (0 to 200) in receive block (2 to 101). If the receive
data in the module is larger than 200 bytes, multiple blocks will be
transferred. Any block with a value of -1 in this field represents the first or
continuation block and the block contains 200 bytes of data. The last
block of data will contain a positive number in this field that represents
the number of characters in the last block.
2 to 101 200 bytes of data received for specified server.
Module
Status
102 to 184 This data area contains the status data block. Each block transferred to
the processor contains this set of information.
185 to 247 Spare data area for future use.
248
Number of characters processed from last write block.
249 Block Sequence Number (Bumped each scan by module)
Word 249 is used as a sequence number for the block of data presented to the
processor. When this number changes, the processor should read the new block
of data. Word 248 of the block informs the PLC processor of the number of bytes
processed from the last write block. Word 0 of the block informs the processor
the source of the data. If the word is set to a value of -1, the block does not
contain any received data and only the status data (words 102 to 184) is
significant in the block. If the word contains a value of 0 to 4, this value
represents the server that received the message. Ladder logic should be written
to handle each enabled server in the module and to process the data received.
Word 1 of the image contains a byte count of the number of characters in the
received message that begins at word 2.