ProSoft inRax MVI94-GSC-E, Руководство пользователя

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MVI94-GSC-E ♦ FLEX Platform Reference
Generic ASCII Comunication Module User Manual
Page 42 of 60
ProSoft Technology, Inc.
July 6, 2009
Byte Offset Description
14 to 15 Application Port transmit state:
0 = Waiting for Data to Send
1 = RTS On
2 = RTS Timeout
3 = Sending data
4 = Waiting for RTS Off
5 = RTS turned off
30 = Intercharacter Delay
31 = Intercharacter Delay
32 = Intercharacter Delay
100 = Message Delay before Transmit
101 = Message Delay before Transmit
Notice that bytes 14 to 15 (word 7) in both of the status blocks contain the Port 2
transmit state. This value can be used to determine when the port is able to
accept more characters to transmit. Each time a write block is transmitted with
data to send to the port, the module will immediately send the data according to
the timing characteristics set for the port and the current message. While the
message is being sent, the Port 2 transmit state will contain a value other than
zero. When the port has completed the full transmission of the write request, the
Port 2 transmit state will have a value of 0.
Write Block
These blocks of data transfer information from the Flex processor to the module.
The structure of the output image used to transfer this data is shown below:
Byte Offset Description
0 Block Sequence Number (Read block number as set by module)
1 Intercharacter delay for this message (milliseconds between
characters with range of 0 to 255).
2 Number of characters to transmit on Application Port (0 to 10)
3 Reserved for future use
Application
Port
4 to 13 Application Port data to transmit
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 byte 0 of the input image to byte 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 byte 0 of the output image. If the number of characters to transmit
in the write block is not set to zero (value in word at byte 2), data to transmit is
present in the block. If the selected port is not busy transmitting data (Port 2
transmit state is zero), the data in the block will be moved to the port’s transmit
buffer and sent out the port. The data to transmit is held in bytes 4 to 13 of the
block.