ProSoft Technology MVI46-GSC - Manual (Page 58)

MVI46-GSC ♦ SLC Platform Reference
Generic Serial Communication Module
Page 58 of 78 ProSoft Technology, Inc.
December 5, 2007
Message timeout used
Settings:
Message timeout = 1000 mSec (Rtimeout=1000)
Data Received on port:
TIME
0
1000 mSec 2000 mSec
A B C D E F G
Comment:
After the 'A' character is received on the port, the message timeout is started.
The characters "ABCDE" will be sent to the controller in one block. The characters
"FG" will follow in the second block one second later.
Intercharacter delay timeout used
Settings:
Intercharacter delay timeout = 300 mSec (Rdelay=300)
Data Received on port:
TIME
0
1000 mSec 2000 mSec
A B C D E F G H
>=300mSec time gap
Comment:
After each character is received, the intercharacter delay timer is reset. The characters
"ABCDEF" will be sent to the controller in one block because the delay timer expires.
The characters "GH" will follow in the second block when the next time gap is recognized.
Packet size limit used
Settings:
Packet size = 4 (RPacketLen=4)
Data Received on port:
A B C D E F G H I J
Comment:
The first block sent to the controller will contain the characters "ABCD", and the second
block will contain the characters "EFGH". The characters "IJ" will not be sent until two
more characters are received on the port.
The maximum size of a message that can be sent using the input image is 4096
bytes. This is the size of the receive buffer in the module. If this buffer is filled
before the termination condition is present, the module will automatically transfer
the received data to the controller. This will prevent the loss of data. The data will
be paged using the M1 file 256 bytes at a time. The ladder logic must handle this
condition if the configuration of the module would permit this situation.