ProSoft Technology MVI46-GSC - Manual (Page 46)

MVI46-GSC ♦ SLC Platform Reference
Generic Serial Communication Module
Page 46 of 78 ProSoft Technology, Inc.
December 5, 2007
M1: File Offset Description
283 Port 2 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
284 Port 2 transmit character count
285 Port 2 transmit block count
286 Port 2 error word
Write Cnt
M1: File Offset Description
287 Port 1 bytes written in last block
288 Port 2 bytes written in last block
The Sequence Block Number (word 0) is an index value used to signal to the
SLC processor that a new block is ready for processing. The ladder logic must
recognize a change in this value and process the data encapsulated in the input
image.
Important: The Sequence Block Number is generated by the module and sent in the
input image. After the ladder has processed inputs and set up outputs, the module
expects to see this number returned back in word offset 100 of the Output Image.
When the module sees this value there, it assumes the ladder has completely
processed the last Input Image and is ready for another. Until it sees the SBN it sent in
the Input Image returned in the Output Image, then it will not set up a new Input Image.
The block contains the data received on each port and status data. The two word
values 1 (port 1 receive length) and 130 (port 2 receive length) define the number
of bytes to be processed by the ladder logic for each port. Receive data for the
ports are found starting at words 2 and 131 for port 1 and 2, respectively. The
ladder logic is responsible for handling all read data transferred from the
communication ports to the processor. The simple example assumes the
received data block is less than or equal to 128 words.