ProSoft Technology ControlLogix MVI56E-SMGC User Manual page 74

MVI56E-SMGC ♦ ControlLogix™ Platform
Enhanced FMC722 TPU General Communication Module
Write Block
These blocks of data transfer information from the ControlLogix processor to the module.
The structure of the output image used to transfer this data is shown in the following
table.
Word
Offset
0
Transmit 1
Data
2
3
4 to 25
26
27
The Block Sequence Number is that received on the last read block transfer through the
input image on the module. The ladder logic should copy this value from word 81 of the
input image to word 0 of output image in the ladder logic. This is the last operation
performed when constructing the write block. The module's program will trigger the
process write block function when a new value is recognized in word 0 of the output
image.
Word 1 of the block defines if the block contains data to write to the Ethernet network. If
the word is set to a value of –1, there is no data in the message. If the word is set to 0,
the block contains one or more data blocks to send out the client. The following table
lists the relationship between word 1 values and their meaning:
Value
-1
0
Word 2 of the block defines the length of all data blocks in the write block. Up to 44 bytes
of data can be sent in each block starting at word offset 4 in the block. It is the
responsibility of the ladder logic to set word 2 to the correct message length and to
populate the data area (words 4 to 25) with the correct data.
Word 3 of the block defines the number of SMGC protocol data blocks contained in the
write block. For simple application of the module, this word should be set to 1 and the
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Description
Block Sequence Number (Read block number as set by module).
Client Number for data to transmit. If the word contains a value of –1,
no transmit data is present. This version of the software only supports
a single client. This word will be set to zero when data is ready for this
client.
Total number of characters contained in the data area (4 to 25) to be
used to build data blocks. Each write block can transmit up to 44 bytes
of data. This parameter has a valid range of 0 to 44. If the parameter is
set to zero, no data will be transmitted.
Number of data blocks contained in this write block. This parameter
specifies the number of individual data blocks present in this block.
Each of these blocks will be parsed and built for transmission to the
TEM server. This parameter has a range of 0 to the maximum number
of data blocks that can be built in the 44 character data area (words 4 to
25). For example, the user can sent this parameter to 1 when sending
SetTagIndex data blocks (44 bytes/block) or to 3 when requesting
Signature data blocks (14 bytes/block).
Data to transmit on specified server or client.
Client[0] Control Word
Module Control Word contains a value of 0, –1 or –2.
Description
No transmit data in block
Client 0 data in block
Reference
User Manual
Page 74 of 98