ProSoft Technology MVI71-GSC - Manual (Page 63)

Reference MVI71-GSC ♦ PLC Platform
Generic Serial Communication Module
ProSoft Technology, Inc. Page 63 of 82
January 31, 2008
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 maximum received data size for the interface. The ladder
logic must handle this condition if the configuration of the module would permit
this situation.
1.16 Cable Connections
The application ports on the MVI71-GSC module support RS-232, RS-422, and
RS-485 interfaces. Please inspect the module to ensure that the jumpers are set
correctly to correspond with the type of interface you are using.
Note: When using RS-232 with radio modem applications, some radios or modems require
hardware handshaking (control and monitoring of modem signal lines). Enable this in the
configuration of the module by setting the UseCTS parameter to 1.